Production and Perception of Vocalic Sequences in Mexican ......iii In support of the first and...

Production and Perception of Vocalic Sequences in Mexican Spanish

by

Anna Limanni

A thesis submitted in conformity with the requirements for the degree of Doctor of Philosophy

Department of Spanish and Portuguese University of Toronto

© Copyright by Anna Limanni 2014

ii

Production and Perception of Vocalic Sequences in Mexican

Spanish

Anna Limanni

Doctor of Philosophy

Department of Spanish and Portuguese

University of Toronto

2014

Abstract

This dissertation investigates variation in the production and perception of vocalic sequences in

Mexican Spanish, with an emphasis on the relationship between this variation and the occurrence

of exceptional hiatuses. The dissertation aims to demonstrate that:

(i) The phonetic variation responsible for the occurrence of exceptional hiatuses is present in all

Spanish varieties, including highly diphthongizing varieties (like Mexican Spanish).

(ii) The phonetic variation leading to the production of exceptional hiatuses is rooted in

patterns of articulation.

(iii) Variation in the production of diphthongs, hiatuses and exceptional hiatuses is related to

variation in their perception.

Three studies were conducted to test these goals. The studies used a variety of experimental and

statistical techniques (including duration and formant normalization procedures, electro-

magnetic articulography, discriminant analysis, signal detection measures, and AX perception

tasks) to provide and evaluate acoustic (Chapter 3), articulation (Chapter 4) and perception

(Chapter 5) data.

iii

In support of the first and second goals, the acoustic and articulation results uncover sequence-

specific and speaker-specific variation in the production of diphthongs and hiatuses, as well as

the presence of exceptional hiatuses. The articulation results also offer evidence for the

articulatory stability of diphthongs and tentatively suggest that the actions of the Tongue Tip

(TT) are crucial for achieving the Diphthong-Hiatus contrast and for diphthongization. While the

results of the perception study do not support the third research goal of establishing a production-

perception link for vocalic sequences in Mexican Spanish, they reveal an unexpected, possibly

dialect-specific Vowel effect which merits further investigation.

Overall, the main findings of this dissertation support the idea that the occurrence of exceptional

hiatuses stems from coarticulatory variation found in all Spanish varieties. These findings

challenge the assumption of an underlying syllabicity contrast between diphthongs and

exceptional hiatuses and question the need for a special category of exceptional hiatuses.

iv

Acknowledgments

Completing this dissertation has been the most challenging activity I have ever undertaken.

Thankfully, I was surrounded by many people who helped and guided me along the way. I could

never have finished this dissertation without them and I wish to express my gratitude for their

presence and support.

First of all, I wish to acknowledge the extraordinary group of scholars whose depth of

knowledge, critical sense, attention to detail and great generosity I took advantage of in

completing this dissertation. I begin by thanking my thesis supervisor, Professor Laura Colantoni

who has inspired and guided my research since my Masters year. I am most grateful for her

ability to help me focus on the big picture of my dissertation during those many times when I got

lost in the experimental details. I am also extremely grateful to my thesis co-supervisor,

Professor Pascal van Lieshout for introducing me to articulatory research, for generously

allowing me access to his lab and for patiently training me on the use of the necessary equipment

and software. I also thank my committee members, Professors Alexei Kochetov and María

Cristina Cuervo for carefully reading the numerous (and extremely long) drafts of the chapters of

this dissertation and for offering many detailed comments and suggestions for revisions along the

way.

I thank Professor Ana Teresa Pérez-Leroux for being a member of my oral examination

committee and for her kind words of encouragement over the years. I also thank Professor

Lourdes Aguilar for agreeing to serve as the external appraiser of my dissertation. I have admired

Professor’s Aguilar research for many years and I feel honoured to have received for her insight

and feedback on my work.

v

Next, I wish to acknowledge members of the Oral Dynamics Lab (Department of Speech

Pathology, University of Toronto). I especially thank Dr. Aravind Namasivayam for volunteering

his time and expertise to help me design and run my experiments. His assistance was invaluable

and I cannot thank him enough. I thank Anneke Slis and Heidi Diepstra for giving me the

opportunity to learn from their experiments. In addition, I am grateful to Aravind, Anneke and

Heidi for their continued friendship and support.

I also owe thanks to my many friends and colleagues. Throughout the years they shared my best

and my worst moments and their unfailing encouragement gave me the strength to keep going in

the face of self-doubt. From the Department of Spanish and Portuguese, I wish to acknowledge

Yadira Álvarez, Tanya Battersby, Natalia Mazzaro, Yasaman Rafat and Irina Marinescu. I wish

to give special thanks to my close friend and ally Chiara Frigeni for her unwavering support and

sound advice.

Finally, and most importantly, I would like to thank my family. I thank my husband, Vicente

García, and my son, Jonathan García-Limanni, for their unyielding support, patience and

encouragement and for tolerating my occasional foul moods. I also thank my parents, Giovanni

and Maria Limanni. Although their circumstances did not allow them to continue their studies

beyond elementary school, they always impressed upon me the importance of an education. I

hope that this work makes them proud.

vi

Table of Contents

Table of Contents

Acknowledgments.......................................................................................................................... iv

Table of Contents ........................................................................................................................... vi

List of Tables ................................................................................................................................ xii

List of Figures ............................................................................................................................. xvii

List of Appendices ....................................................................................................................... xxi

Chapter 1 Introduction .....................................................................................................................1

1 Overview .....................................................................................................................................1

2 Sound Variation and Change ......................................................................................................2

2.1 Dialectal Variation and Sound Change ................................................................................4

3 Vocalic Sequences in Spanish .....................................................................................................4

4 Experimental Focus and Design..................................................................................................8

4.1 Dialect and Participant Selection .......................................................................................10

5 Dissertation Outline ..................................................................................................................11

Chapter 2 Literature Review ..........................................................................................................12

1 Introduction ...............................................................................................................................12

2 Theoretical Approaches to Vocalic Sequences .........................................................................13

2.1 Spanish ...............................................................................................................................13

2.1.1 The Phonemic Status of Spanish Glides ................................................................16

2.1.2 Alternating Diphthongs (‘los diptongos alternantes’) in Spanish ..........................22

2.1.3 The Syllabic Representation of Spanish Diphthongs.............................................24

2.2 Other Romance Languages ................................................................................................26

2.2.1 Italian .....................................................................................................................26

vii

2.2.2 Romanian ...............................................................................................................29

2.2.3 French ....................................................................................................................30

2.2.4 Portuguese ..............................................................................................................31

2.3 Non-Romance Languages ..................................................................................................32

2.3.1 English ...................................................................................................................32

2.3.2 Dutch ......................................................................................................................34

2.3.3 German ...................................................................................................................35

2.4 Summary ............................................................................................................................36

3 Experimental Studies ................................................................................................................37

3.1 Acoustic Studies.................................................................................................................37

3.1.1 Frequency Parameters ............................................................................................38

3.1.2 Temporal Parameters .............................................................................................41

3.1.3 Summary ................................................................................................................43

3.2 Articulation Studies ...........................................................................................................44

3.2.1 Summary ................................................................................................................49

3.3 Perception Studies ..............................................................................................................49

3.3.1 Spanish ...................................................................................................................50

3.3.2 Italian .....................................................................................................................55

3.3.3 Romanian ...............................................................................................................57

3.3.4 Non-Romance Languages ......................................................................................59

3.3.5 Summary ................................................................................................................63

4 Conclusions ...............................................................................................................................63

Chapter 3 Acoustic Analysis of Vocalic Sequences in Mexican Spanish .....................................66

1 Introduction ...............................................................................................................................66

2 Experimental Methodology .......................................................................................................68

2.1 Participants .........................................................................................................................68

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2.2 Stimuli ................................................................................................................................68

2.3 Tasks and Procedures .........................................................................................................69

2.4 Measurements and Analyses ..............................................................................................71

2.4.1 Temporal Measurements ........................................................................................72

2.4.2 Frequency Measurements ......................................................................................74

2.4.3 Discriminant Analysis ............................................................................................77

3 Results .......................................................................................................................................78

3.1 Sequence Duration .............................................................................................................78

3.1.1 Vowel Effects on Sequence Duration ....................................................................84

3.2 Transition Duration ............................................................................................................88

3.2.1 Vowel Effects on Transition Duration ...................................................................90

3.3 Frequency ...........................................................................................................................94

3.3.1 Diphthong (já, jé, jó) vs. Hiatus (í.a ,í.e, í.o) .........................................................94

3.4 Discriminant Analysis ......................................................................................................102

3.4.1 Data Preparation and Procedures .........................................................................102

3.4.2 Discriminant Analysis Results .............................................................................105

3.4.3 Misclassified Sequences ......................................................................................107

4 Summary and Discussion ........................................................................................................111

4.1 Hypothesis 1: Diphthong vs. Hiatus ................................................................................111

4.2 Hypothesis 2: Vowel Effects ...........................................................................................112

4.3 Hypothesis 3: Exceptional Hiatuses.................................................................................113

4.4 Discussion ........................................................................................................................115

5 Conclusions .............................................................................................................................118

Chapter 4 Articulatory Analysis of Vocalic Sequences in Mexican Spanish ..............................120

1 Introduction .............................................................................................................................120

2 Experimental Methodology .....................................................................................................124

ix

2.1 Participants .......................................................................................................................124

2.2 Stimuli ..............................................................................................................................124

2.3 Instrumentation and Procedure ........................................................................................124

2.4 Data Processing ................................................................................................................127

2.5 Measurement and Analysis ..............................................................................................128

3 Results .....................................................................................................................................130

3.1 Timing (TB-TT Offset) ....................................................................................................130

3.1.1 Vowel Effects on Timing of TB and TT ..............................................................140

3.2 Spatial Displacement (%TT and %TB) ...........................................................................143

3.2.1 Vowel Effects on Spatial Displacement of TB and TT .......................................151

3.3 Discriminant Analysis ......................................................................................................156

3.3.1 Sequences with [a] ...............................................................................................157

3.3.2 Sequences with [e] ...............................................................................................159

3.3.3 Sequences with [o] ...............................................................................................162


4.1 Hypothesis 1: Timing of TB and TT................................................................................163

4.2 Hypothesis 2: Magnitude of TT and TB Displacement ...................................................164

4.3 Hypothesis 3: Exceptional Hiatuses.................................................................................165

4.4 Discussion ........................................................................................................................168

5 Conclusions .............................................................................................................................171

Chapter 5 Perception of Vocalic Sequences in Mexican Spanish ...............................................173

1 Introduction .............................................................................................................................173

2 Experimental Methodology .....................................................................................................179

2.1 Participants .......................................................................................................................179

2.1.1 Hearing Screening ................................................................................................179

2.1.2 Handedness Questionnaire ...................................................................................180

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2.2 Stimuli ..............................................................................................................................181

2.3 Tasks and procedures .......................................................................................................187

2.4 Analysis............................................................................................................................188

2.4.1 Discrimination Measures .....................................................................................189

2.4.2 Statistical Analysis ...............................................................................................195

3 Results .....................................................................................................................................195

3.1 Hypothesis 1: Pair Type Effects ......................................................................................195

3.1.1 Stimulus Type and ISI Effects on Pair Type .......................................................199


3.2.1 ISI and Stimulus Type Effects on V ....................................................................207

3.2.2 Interactions between Pair Type and V .................................................................210


4.1 Hypothesis 1: Diphthong vs. Hiatus ................................................................................216


4.3 Hypothesis 3: Production-Perception Link ......................................................................218

4.4 Discussion ........................................................................................................................219

5 Conclusions .............................................................................................................................221

Chapter 6 Conclusions .................................................................................................................222

1 Introduction .............................................................................................................................222

2 Summary of Findings ..............................................................................................................222

2.1 Phonetic Variation and Exceptional Hiatuses ..................................................................222

2.1.1 Sequence-specific Variation ................................................................................223

2.1.2 Speaker-specific Variation ...................................................................................224

2.2 Articulation and Exceptional Hiatuses.............................................................................225

2.3 Production-Perception Link .............................................................................................226

3 Contributions ...........................................................................................................................229

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3.1 Empirical Contributions ...................................................................................................229

3.2 Theoretical Contributions ................................................................................................230

3.3 Methodological Contributions .........................................................................................230

4 Future Directions .....................................................................................................................231

References ....................................................................................................................................232

Appendices ...................................................................................................................................246

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List of Tables

Table 1. Means and SDs of syllables per second produced by Speakers, by Speech Rate .......... 71

Table 2. Means and SDs of raw and normalized sequence duration for Diphthong and Hiatus, by

Speech Rate ................................................................................................................................... 78

Table 3. ANOVA table for differences between Diphthong and Hiatus in raw sequence duration

(ms), by Speech Rate .................................................................................................................... 79

Table 4. ANOVA table for differences between Diphthong and Hiatus in sequence duration

(normalized), by Speech Rate ....................................................................................................... 82

Table 5. Means and SDs for sequence duration (normalized) of Diphthong and Hiatus, by

Sequence Type, Rate and V .......................................................................................................... 84


(normalized), by Speech Rate and V ............................................................................................ 85

Table 7. Bonferroni post-hoc tests for differences between Diphthong and Hiatus in sequence

duration (normalized), by Speech Rate and V .............................................................................. 86

Table 8. Means and SDs of %Transition for Diphthong and Hiatus, by Speech Rate ................ 88

Table 9. ANOVA table for differences between Diphthong and Hiatus in %Transition, by Speech

Rate ............................................................................................................................................... 89

Table 10. Means and SDs for %Transition of Diphthong and Hiatus, by Sequence Type, Rate

and V ............................................................................................................................................. 91

Table 11. ANOVA table for differences between Diphthong and Hiatus in %Transition, by

Speech Rate and V ........................................................................................................................ 92

Table 12. Bonferroni post-hoc tests for differences between Diphthong and Hiatus in

%Transition, by Speech Rate and V ............................................................................................. 93

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Table 13. ANOVA results for differences between Diphthong and Hiatus in F1 and F2, by

Speech Rate and V ........................................................................................................................ 96

Table 14. Bonferroni post-hoc comparisons of differences in F1 and F2 between Diphthong and

Hiatus, by V .................................................................................................................................. 97

Table 15. Mean values of the polynomial equation constants and coefficients of F1 and F2 for

Diphthong and Hiatus, by V ....................................................................................................... 103

Table 16. ANOVA table for differences between Diphthong and Hiatus in the polynomial

constants and coefficients of F1 and F2 trajectories ................................................................... 104

Table 17. Significant predictors for inclusion in discriminant analysis, by V (acoustics) ......... 105

Table 18. Discriminant analysis summary table for V= [a] (acoustics) ..................................... 105

Table 19. Discriminant analysis summary table for V= [e] (acoustics) ..................................... 106

Table 20. Discriminant analysis summary table for V= [o] (acoustics) .................................... 106

Table 21. Summary of discriminant analysis classification (predicted group membership) of

Diphthong and Hiatus: V= [a] (acoustics) .................................................................................. 108

Table 22. Summary of misclassified sequences with [a], by Speaker (acoustics) ...................... 108


Diphthong and Hiatus: V= [e] (acoustics) .................................................................................. 109

Table 24. Summary of misclassified sequences with [e], by Speaker (acoustics) ...................... 110


Diphthong and Hiatus: V= [o] (acoustics) .................................................................................. 110

Table 26. Summary of misclassified sequences with [o], by Speaker (acoustics) ..................... 111

Table 27. EMA static system noise average SDs (in millimeters), by Speaker.......................... 128

Table 28. Means and SDs of TB-TT offset (ms) for Diphthong and Hiatus, by Speech Rate ... 130

xiv

Table 29. ANOVA table for differences between Diphthong and Hiatus in TB-TT offset (ms), by

Speech Rate ................................................................................................................................. 132

Table 30. Means and SDs of TB-TT offset (absolute values) for Diphthong and Hiatus, by

Speech Rate ................................................................................................................................. 138

Table 31. ANOVA table for differences between Diphthong and Hiatus in TB-TT offset

(absolute values), by Speech Rate .............................................................................................. 139

Table 32. Means and SDs of TB-TT Offset (absolute values) for Diphthong and Hiatus, by

Speech Rate and V ...................................................................................................................... 140


(absolute values), by Speech Rate and V .................................................................................... 142

Table 34. Means and SDs of maximum TT and TB displacement (%) for Diphthongs and Hiatus,

by Speech Rate ............................................................................................................................ 143

Table 35. ANOVA table for differences between Diphthong and Hiatus in maximum TB and TT

displacement (%), by Speech Rate .............................................................................................. 145

Table 36. Means and SDs of TT displacement at peak TB displacement (%) for Diphthong and

Hiatus, by Sequence Type and Rate ........................................................................................... 149

Table 37. ANOVA table for differences between Diphthong and Hiatus in TT displacement at

peak TB displacement (%), by Speech Rate ............................................................................... 150

Table 38. Means and SDs of TB and TT displacement (%) for Diphthong and Hiatus by Speech

Rate and V................................................................................................................................... 152

Table 39. ANOVA table for differences between Diphthong and Hiatus in TB displacement and

TT displacement at peak TB (%), by Speech Rate and V .......................................................... 154

Table 40. Discriminant analysis summary table for V= [a], using TB-TT offset (absolute) and

%TT at peak TB as predictors (articulation) ............................................................................... 157

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Diphthong and Hiatus for V = [a] (articulation) ......................................................................... 158

Table 42. Summary of misclassified sequences with [a], by Speaker (articulation) .................. 159

Table 43. Discriminant analysis summary table for V= [e], using TB-TT offset (absolute) as

predictor (articulation) ................................................................................................................ 159


Diphthong and Hiatus for V = [e] (articulation) ......................................................................... 161

Table 45. Summary of misclassified sequences with [e], by Speaker (articulation) .................. 162

Table 46. Discriminant analysis summary table for V= [o], using TB-TT offset (absolute) as

predictor (articulation) ................................................................................................................ 162


Diphthong and Hiatus for V = [o], (articulation) ........................................................................ 163

Table 48. Summary of misclassified sequences with [o], by Speaker (articulation) .................. 163

Table 49. Temporal characteristics (sequence and transition duration) of nonsense word stimuli

for AX perception task ................................................................................................................ 182

Table 50. Durational differences between categories of Sequence Type (normalized

measurements) for AX perception task ....................................................................................... 182

Table 51. Stimuli list for AX perception task ............................................................................. 185

Table 52. Categorization of correct and incorrect responses for AX perception tasks ............... 189

Table 53. Summary of AX perception task responses, by Response type and Participant across all

conditions .................................................................................................................................... 189

Table 54. Summary of response accuracy (p(c)), sensitivity (A') and bias (β″D) scores by

Participant, across all conditions................................................................................................. 193

Table 55. Summary of p(c), A′ and β″D scores for Pair Type (A = X) ....................................... 196

xvi

Table 56. Summary of p(c), A′ and β″D scores for Pair Type (A≠X) ......................................... 197

Table 57. Summary of p(c), A′ and β″D scores for Stimulus Type (Sequence vs. Word) and ISI

(500 vs. 1000) ............................................................................................................................. 200

Table 58. Summary of p(c), A′ and β″D scores for Pair Type (A≠X), by Stimulus Type (Word vs.

Sequence) and ISI (500 vs. 1000), across Participants ............................................................... 202

Table 59. Summary of p(c), A′ and β″D scores for Pair Type (A≠X), by Stimulus Type (Sequence

vs. Word) and ISI (500 vs. 1000), by Participant ....................................................................... 203

Table 60. Summary of p(c), A′ and β″D scores for V ([a], [e], [o]) ............................................. 206

Table 61. Summary of p(c), A′ and β″D scores for V, by Stimulus Type and ISI, across

participants .................................................................................................................................. 208

Table 62. Wilcoxon Signed Ranks Test results (Bonferroni corrections: α = 0.05/12 = 0.004) for

differences between levels of V by ISI and Stimulus Type ........................................................ 209

Table 63. Results of Wilcoxon Signed Ranks Test results (Bonferroni corrections: α = 0.05/6 =

0.008) for differences within levels of V by ISI and Stimulus Type .......................................... 209

Table 64. Summary of p(c), A′ and β″D scores for V by Stimulus Type and ISI, by Participant 210

Table 65. Summary of p(c), A' and β″D scores for V by Pair Type, across participants............. 211

Table 66. Wilcoxon Signed Ranks Tests results (Bonferroni correction: α = 0.05/18 = 0.003) for

differences between levels of V by Pair Type ............................................................................ 214

Table 67. Summary of p(c), A' and β″D scores for V by Pair Type, by Participant .................... 215

xvii

List of Figures

Figure 1. Spectrogram of a token of [jó] produced by speaker CG, showing the boundaries for

sequence and transition duration measurements ........................................................................... 73

Figure 2. Spectrogram of a token of [jó] produced by speaker CG, showing the 10 intervals

where F1 and F2 frequency measurements were made ................................................................ 75

Figure 3. Bar chart of mean sequence duration (ms) by Sequence Type and Speech Rate .......... 79

Figure 4. Bar chart of mean sequence duration (ms) by Sequence Type, Speech Rate and Speaker

....................................................................................................................................................... 81

Figure 5. Bar chart of mean sequence duration (normalized) by Sequence Type and Rate ......... 82

Figure 6. Bar chart of mean sequence duration (normalized) by Sequence Type, Speech Rate and

Speaker .......................................................................................................................................... 83

Figure 7. Bar chart of mean duration (normalized) by Sequence Type, Speech Rate and V ....... 85

Figure 8. Bar chart of mean duration (normalized) by Sequence Type, V and Speaker: ............. 87

Figure 9. Bar chart of mean %Transition by Sequence Type and Speech Rate ........................... 89

Figure 10. Bar chart of mean % Transition by Sequence Type, Speech Rate and Speaker ......... 90

Figure 11. Bar chart of mean % transition by Sequence Type, Speech Rate and V ..................... 91

Figure 12. Bar chart of mean %Transition for Sequence Type, V and Speaker: .......................... 94

Figure 13. Scatterplot of F1-F2 formant changes from sequence onset to offset, by Sequence

Type and V .................................................................................................................................... 95

Figure 14. Scatterplot of F1-F2 of Sequence Type, for V = [a] ................................................... 98

Figure 15. Scatterplot of F1-F2 of Sequence Type, for V = [a] by Speaker ................................. 99

Figure 16. Scatterplot of F1-F2 of Sequence Type, for V = [e] ................................................. 100

xviii

Figure 17. Scatterplot of F1-F2 of Sequence Type, for V = [e] by Speaker ............................... 100

Figure 18. Scatterplot of F1-F3 of Sequence Type, for V = [o] ................................................. 101

Figure 19. Scatterplot of F1-F2 of Sequence Type, for V = [o] by Speaker .............................. 102

Figure 20. Coil placement for 3D EMA ..................................................................................... 125

Figure 21. Waveform and articulatory movement data from vertical axis of a token of [já] from

the word piano produced by speaker CG, showing the temporal and spatial measurements used to

analyze the data. .......................................................................................................................... 129

Figure 22. Bar chart of mean TB-TT offset (ms) by Sequence Type and Speech Rate ............. 131

Figure 23. Bar chart of mean TB-TT offset (ms) for Sequence Type, by Speech Rate and Speaker

..................................................................................................................................................... 133

Figure 24. Interaction plot of Mean TB-TT offset (ms) for Sequence Type, by Speaker: Rate 1

..................................................................................................................................................... 134

Figure 25. Interaction plot of Mean TB-TT offset (ms) for Sequence Type, by Speaker: Rate 2

..................................................................................................................................................... 134

Figure 26. Waveform and articulatory movement data (vertical dimension) of a token of [jó]

from viola showing anticipatory TT movement, Speaker CG, Rate 2........................................ 136


from viola showing TT lead, Speaker AA, Rate 2 ...................................................................... 137

Figure 28. Bar chart of Mean TB-TT offset (absolute values) for Sequence Type, by Speech Rate

..................................................................................................................................................... 138


and Speaker ................................................................................................................................. 140


and V ........................................................................................................................................... 141

xix

Figure 31. Bar chart of Mean TB-TT offset (absolute values) for Sequence Type, by Speech

Rate, V and Speaker .................................................................................................................... 143

Figure 32. Bar chart of mean magnitude of TT and TB displacement (%) for Sequence Type, by

Speech Rate ................................................................................................................................. 144

Figure 33. Bar chart of mean magnitude of TT and TB displacement (%) for Sequence Type, by

Speaker: Rate 1 and Rate 2 ......................................................................................................... 147


from viola with no reduction of %TT, Speaker MM, Rate 1 ...................................................... 148


from viola with reduction of %TT, Speaker AN, Rate 1 ............................................................ 148

Figure 36. Bar chart of mean magnitude of TB displacement (%) and TT displacement (%) at

peak TB displacement for Sequence Type, by Speech Rate ....................................................... 150


peak TB displacement for Sequence Type, by Speech Rate and Speaker .................................. 151


peak TB displacement for Sequence Type, by Speech Rate and V ............................................ 153

Figure 39. Bar chart of mean magnitude of TB displacement and TT displacement at peak TB

displacement for Sequence Type, by Speech Rate and Speaker, V = [a] ................................... 155


displacement for Sequence Type, by Speech Rate and Speaker, V = [e] ................................... 155


displacement for Sequence Type, by Speech Rate and Speaker, V = [o] ................................... 156

Figure 42. Scatterplot of F1-F2 of AX perception task stimuli, by Sequence Type: V = [a] ..... 183

Figure 43. Scatterplot of F1-F2 of AX perception task stimuli, by Sequence Type: V = [e] ..... 184

xx

Figure 44. Scatterplot of F1-F2 of AX perception task stimuli, by Sequence Type: V = [o] ..... 184

Figure 45. Pie chart of AX perception task responses (%) by Response Type, across all

conditions .................................................................................................................................... 190

Figure 46. Bar chart of AX perception task responses (%) by Response Type and Participant,

across all conditions .................................................................................................................... 191

Figure 47. Bar chart of mean p(c), A' and β″D scores, across all conditions ............................... 194

Figure 48. Bar chart of mean p(c), A' and β″D scores for Pair Type (A≠X) ............................... 197

Figure 49. Bar chart of mean p(c), A' and β″D scores for V ........................................................ 205

Figure 50. Bar chart of mean p(c), A' and β″D scores for V by ISI and Stimulus Type .............. 207

Figure 51. Bar chart of mean p(c), A' and β″D scores for V by Pair Type, V = [a] .................... 212

Figure 52. Bar chart of mean p(c), A' and β″D scores for V by Pair Type, V = [e] .................... 212

Figure 53. Bar chart of mean p(c), A' and β″D scores for V by Pair Type, V = [o] .................... 213

Figure 54. Bar chart of mean p(c) scores for V, by Speaker Dialect and Listener Dialect ........ 228

xxi

List of Appendices

Appendix 1: Experiment Stimuli (Chapters 3 and 4).................................................................. 246

Appendix 2: Table of Individual Means and Standard Deviations (Chapter 3) ......................... 247

Appendix 3: Tables of Individual Means and Standard Deviations (Chapter 4) ........................ 250

Appendix 4: Hearing Screening (Chapter 5) .............................................................................. 255

Appendix 5: Handedness Questionnaire (Chapter 5) .................................................................. 256

1

Chapter 1 Introduction

1 Overview

This dissertation is concerned with variation in the production and perception of vocalic

sequences, diphthongs and hiatuses, in Mexican Spanish. Specifically, it investigates the

relationship between this variation and the occurrence of a particular category of vocalic

sequences referred to as exceptional hiatuses.

Vocalic sequences figure prominently in Romance phonology (e.g. Gili Fivela & Bertinetto,

1998 for Italian; Chitoran, 2002 for Romanian; Azevedo, 2005 for Portuguese; Walker, 2001 for

French) in large part because they highlight a complex and often less-than-straightforward

relationship between stress assignment, syllable affiliation and high vocoid sonority in these

languages1. As a result, much has already been written on the topic of vocalic sequences in

Spanish, including exceptional hiatuses (e.g. Aguilar, 1999; Hualde & Prieto, 2002; Cabré &

Prieto, 2006; Chitoran & Hualde, 2007; Garrido, 2007; Colantoni & Limanni, 2010, among

many others).

This dissertation both complements and challenges those previous studies in three interrelated

ways. First, it investigates the production and perception of Spanish vocalic sequences through a

combination of acoustic, articulatory and perception data. As such, the present work adds to

previous studies which have focused mainly on acoustic analysis and syllabification intuitions. It

also highlights the importance of a comprehensive experimental approach which makes use of a

variety of methodological and statistical techniques, including EMA (electro-magnetic

articulography), Discriminant Analysis and Signal Detection Theory measures. Second, this

dissertation analyzes the occurrence of exceptional hiatuses as a phonetically-driven

phenomenon rooted in variation in the production and perception of diphthongs and hiatuses.

Third, it emphasizes how exploring phonetic variation within a specific variety (or dialect, in this

case) of a language contributes to an understanding of how a sound change emerges within and

1 A detailed presentation of the theoretical and experimental literature on vocalic sequences in Spanish and other Romance

languages is provided in Chapter 2.

2

across other varieties or dialects of the same language. In relation to the last two points, this

dissertation proposes that the occurrence of exceptional hiatuses is driven by coarticulatory

variation found in all Spanish varieties, even in those varieties described as highly

diphthongizing and, thus, predicted to produce few of these sequences. This proposal challenges

the view prevalent in Spanish phonology that it is necessary to assume an underlying syllabicity

contrast between diphthongs and exceptional hiatuses (e.g. Harris & Kaisse, 1999; Hualde,

2005). Ultimately, it also calls into question the need for a special category of exceptional

hiatuses.

The dissertation is motivated and informed largely by research which:

1. emphasizes phonetic explanations for the origins of sound variation and change (e.g.

Ohala, 1989; Browman & Goldstein, 1991; Widdison, 1995; Blevins, 2004),

2. examines the link between speech perception and speech production in sound variation

and change (e.g. Beddor et al., 2002; Beddor, 2012),

3. stresses the value of reexamining issues in Spanish phonology through an experimental

lens (e.g. Widdison, 1995, 1997; Eddington, 2004), and

4. studies synchronic dialectal variation and its link to sound change (e.g. Romero, 1995;

Brown & Torres Cacoullos, 2003; Colantoni, 2006).

The present chapter is organized as follows: §2 briefly outlines the research and associated

assumptions which motivated the dissertation; §3 provides an overview of vocalic sequences in

Spanish and explains their suitability as the focus of study; §4 outlines the experimental

methodology, provides a rationale for dialect and participant selection, and presents the main

hypotheses being tested; and, §5 closes the chapter with an outline of the remainder of the

dissertation.

2 Sound Variation and Change

The speech signal is undeniably and inherently variable (Ohala, 1981, 1989, 1993). One source

of this variation is the speaker. Some of this speaker-related variation is apparent. For example,

we recognize speakers of different languages varieties or dialects by the way they pronounce

certain sounds. Even individual speakers of the same variety produce the same sound differently,

such that we might identify one speaker as ‘a clear speaker’ and another as ‘hard to understand’.

Of special interest for developing and testing theories of sound variation and change, however, is

3

the kind of speaker variation that is below the level of awareness, also referred to as “hidden

variation” (Ohala, 1989). This kind of variation is internally motivated and phonetic in nature,

largely rooted in coarticulatory processes (Browman & Goldstein, 1991; Mowrey & Pagliuca,

1995; Beddor, 2012; Ohala, 2012; Recasens, 2012). The speaker, being subject to various

physical constraints related to the vocal tract, produces “an unlimited number of measurably

different phonetic variants of each word in actual speech” (Ohala, 1981, p. 179). These variants

constitute the “pool of synchronic variation” (Ohala, 1989) from which a potential sound change

is drawn.

Another source of variation is the listener. For Ohala (1989), the role of the listener is crucial for

determining whether the phonetic variability present in the speech signal triggers a sound change

or not. In his view, if the listener misinterprets the noise/ambiguity in the speech signal as

intentional, then a sound change is possible. This process is affected by individual differences as

well. For example, different listeners may use different perceptual strategies to deal with the

range of variation in production to the extent that the same phonetic cue may have different

perceptual effects from one listener to another (Beddor et al., 2002; Beddor, 2012). In addition,

some listeners may be more attuned to coarticulatory factors than others. In fact, recent

experimental studies suggest that there is a link between how a contrast is perceived and how it

is produced (Beddor et al., 2002; Beddor, 2012; Newman, 2003; Perkell et al., 2004a, 2004b,

2006).

Regardless of whether we believe that sound change is mainly listener-driven (Ohala, 1989;

Blevins, 2007) or mainly speaker-driven (Lindblom, 1990), non-teleological (Ohala, 1989) or

goal-oriented (Lindblom et al., 1995), the importance of this synchronic variation in production

and perception is its crucial role in the initiation of sound change (Ohala, 1989). This link

between synchronic variation and historical sound change means that the source of a sound

change which has already taken place and is distinguishing feature of the phonology of a

particular language can be investigated experimentally by studying a language where the same

phenomenon appears at the level of phonetic variation. For example, investigations into the

production and perception of nasalization (e.g. Beddor et al., 2002) in languages with synchronic

context-dependent nasalization of vowels can shed light onto the origins of distinctively nasal

vowels in French. Similarly, the phenomenon of syllable-final [s] aspiration and deletion found

in present-day varieties of Spanish can provide insight into a similar process which occurred in

4

Old French (e.g. Romero, 1995). This methodology can also be extended to study varieties or

dialects of the same language to explore a sound change which has occurred or is in progress in

one dialect but not in another.

2.1 Dialectal Variation and Sound Change

An underlying premise of this dissertation is that the phonetic variation that results in exceptional

hiatuses, an observable feature of Peninsular Spanish, is present as “hidden” variation in other

varieties of Spanish (i.e. Mexican Spanish, a diphthongizing variety). The study of synchronic

dialectal variation to understand sound change has numerous experimental precedents for

Spanish. This approach can be found in studies of other phenomena in Spanish, including [s]-

aspiration and deletion (Romero, 1995; Brown & Torres Cacoullos, 2003; Torreira, 2006) and

assibilation of rhotics and palatals (Colantoni, 2006). Importantly, these studies have shown that

the phonetic characteristics associated with [s]-aspiration and assibilation of rhotics and palatals

can be found (to different degrees) in corresponding non-aspirating and non-assibilating varieties

of Spanish. The present dissertation proposes that, just as the pre-conditions for [s] aspiration are

present in non-aspirating varieties of Spanish, so too the pre-conditions for exceptional hiatuses

are found in diphthongizing varieties of Spanish. An examination of these varieties can help

determine why exceptional hiatuses occur and persist in Peninsular Spanish and what their

phonetic origins may be.

3 Vocalic Sequences in Spanish

Sequences of two vowels in Spanish may be syllabified within a single syllable or in two

separate syllables. In the first case, the result is called a diphthong (e.g. Mario, [má.ɾjo]) and in

the second case the result is referred to as a hiatus (e.g. María, [ma.ɾí.a]). Syllabification of these

sequences is said to be largely predictable, as long as stress assignment is known and the

sonority of the vocoids making up the vocalic sequence is also taken into account. This

syllabification generally adheres to the following two prescriptive rules (based on Hualde 2005,

p. 78-80):

(1) a hiatus occurs when

(a) both vowels are [-high] (/a e o/), as in fea [fé.a], ‘ugly-fem.sing.’ or teatro

[te.á.tɾo] ‘theatre’; toalla [to.á.ʝa], ‘towel’

5

(b) a stressed [+high] vowel (/í ú/) is followed or preceded by a [-high] vowel

(/a e o/)2, as in frío [fɾí.o], ‘cold-masc.sing.’, baúl [ba.úl] ‘trunk’, or maíz

[ma.ís] ‘corn’

(2) in all other cases, a [+high] vowel is realized as a glide [j w] and the sequence is a

diphthong, as in diente [djén.te] ‘ tooth’, peine [péj.ne] ‘comb’, duelo [dwé.lo] ‘duel’,

or neutro [néw.tɾo].

Spanish diphthongs are generally described as glide-vowel (GV) sequences while hiatuses in this

language are described as concatenations of two single vowels or vowel-vowel (VV) sequences3

(e.g. Hualde, 2005). Spanish diphthongs may be either: (i) rising diphthongs consisting of a GV

sequence, as in piedra [pjé.ðɾa] ‘stone’ or (ii) falling diphthongs consisting of a VG sequence, as

in peine [péj.ne] ‘comb’4. Similarly, hiatuses can differ according to which vowel is stressed: (i)

the first vowel, as in fea [fé.a], ‘ugly-fem.sing.’; (ii) second vowel, as in teatro [te.á.tɾo]

‘theatre’, or (iii) neither vowel, as in fealdad [fe.al.ðáð], ‘ugliness’.

In terms of phonological status, the diphthong-hiatus contrast represented in 1b and 2 is the most

robust. For example, there are some minimal pairs in the language which contrast GV and VV

sequences:

(3) GV sequence VV sequence

varias [vá.ɾjas] ‘various-fem.’ varías [va.ɾí.as] ‘you vary’

amplio [ámpljo] ‘broad/wide’ amplío [amplí.o] ‘I broaden/widen’

continuo [kon.tí.nwo] ‘continuous’ continúo [kon.ti.nú.o] ‘I continue’

Also, these sequences are distinguished by orthographic convention since stressed high vowels

followed or preceded by a non-high vowel are always marked. Studies on the acoustic properties

of this contrast also suggest that the Diphthong-Hiatus contrast between 1b and 2 above is

relatively predictable at the phonetic level. These studies report that, in general: (i) diphthongs

2 Sequences of two [+high] vowels also occur: cuida [kwí. ða] ‘s/he cares for’; viuda [vjú.ða], ‘widow’ (Hualde, 2005). These

sequences are generally pronounced as rising (Hualde, 2005) but the rising-falling distinction is often blurred (Hualde et al.,

2001) and for this reason they are not included in the present study.

3 The definition of diphthong and hiatus may differ in other languages. Chapter 2 provides a review of how vocalic sequences are

defined in other Romance and non-Romance languages.

4 The terms ‘rising’ and ‘falling’, as they apply to vocalic sequences in Spanish and other Romance languages, are defined

according to sonority (e.g. Hualde, 2005).

6

are shorter than hiatuses (Aguilar, 1999; Hualde & Prieto, 2002); (ii) diphthongs devote a larger

portion of the sequence to the transition between the two vocalic elements than hiatuses (Aguilar,

1999), and (iii) diphthongs have a less steep second formant (F2) slope than hiatuses (Aguilar,

1999).

In reality, however, there is also a great deal of dialectal and individual variation in the

production of these sequences. This variation has been found to occur between speakers of

different dialects (Cabré & Prieto, 2006), between speakers of different varieties of the same

dialect (Garrido, 2007; Colantoni & Limanni, 2010), between speakers of the same variety of a

dialect (Hualde & Prieto, 2002; Macleod, 2007) and within individual speakers of a single dialect

(Hualde, 1999; Macleod, 2007). This variation is found in (i) rates of diphthongization of

hiatuses (Colantoni & Limanni, 2010; Garrido, 2007, 2008) and (ii) the way the diphthong-hiatus

contrast is realized (Colantoni & Limanni, 2010). Interestingly, we observe what appear to be

two competing tendencies in the realization of vocalic sequences both between and within

Spanish varieties, especially as regards the application of the above syllabification rules in 1a

and 2.

On the one hand, there is a diphthongizing tendency in those cases where both vowels in the

sequences are [-high], as in 1a above (Garrido, 2007, 2008; Hualde et al., 2008; García &

Figueroa, 2001; Lope Blanch, 1996). In those cases, the mid vowel in a sequence of [-high]

vowels may become a glide, [e] or [o] (as in teatro [teá.tɾo] and toalla [toá.ʝa], respectively).

Subsequently, the glided mid vowel may raise to [j] and [w], as in teatro [tjá.tɾo] and toalla

[twá.ʝa]5. These changes are subject to individual (Hualde et al., 2008) and dialectal (Garrido,

2007, 2009) variation and are more likely to occur in more casual speech styles and/or faster

speech rates (Aguilar, 1997, 1999). Diphthongization may also occur where a stressed high

vowel follows a non-high vowel, as in maíz [ma.ís] > [májs] ‘corn’ (Garrido, 2007. p. 30). In the

latter case, diphthongization involves a stress shift from the high vowel to the non-high vowel

and gliding of the high vowel ([i] > [j]). This diphthongizing tendency is a synchronic reflection

of the historical preference for diphthongizing hiatuses from all sources. Among these are

5 Other hiatus resolution strategies may also be employed, including elision of one of the vocoids, as in creer > [kɾeɾ] (Garrido,

2008, p.11) and consonant insertion, as in María > [ma.ɾí.ja] (Frago Gracia & Franco Figueroa, 2001, p.87) or canoa > [ka.nó.βa]

(Garrido, 2008, p. 11). However, diphthongization, arguably the most common strategy, is the only one explored here.

7

hiatuses originating from Latin heterosyllabic sequences (ITALIA > [i.tá.li.a] > [i.tá.lja] ‘Italy’)

and those resulting from the deletion of intervocalic consonants (REGINA > [re.í.na] > [réj.na]

‘queen’).

On the other hand, we also find a tendency to produce hiatus where a diphthong is expected.

Specifically, for some speakers there appear to be some lexical exceptions to the rule in 2 above.

These exceptions result in the production of what are generally referred to as exceptional

hiatuses in Spanish phonology (e.g. Hualde, 1999; Hualde & Prieto, 2002; Cabré & Prieto, 2006;

Chitoran & Hualde, 2007)6. Speakers who produce exceptional hiatuses might, for example,

pronounce dueto ‘duet’ as [du.é.to] instead of as [dwé.to] and cliente ‘client’ as [kli.én.te] instead

of as [kljén.te]. Unlike the diphthongization tendency mentioned above which is found (albeit to

varying degrees, e.g. Colantoni & Limanni, 2010) across all Spanish varieties, this hiatization

tendency is a phenomenon generally associated with speakers of Peninsular Spanish. For

example, a Peninsular Spanish speaker may say piano ‘piano’ with a hiatus ([pi.áno]) where an

Argentine speaker would produce the same word with the expected diphthong ([pjá.no]). In the

Spanish phonology literature, these exceptional hiatuses are widely considered to contrast with

diphthongs7 (e.g. Harris & Kaisse, 1999; Hualde & Prieto, 2002; Hualde, 2005; Chitoran &

Hualde, 2007). These authors point to near-minimal pairs (e.g. from Harris & Kaisse, 1999:

vaciaba [ba.θi.á.βa] ‘s/he emptied’ vs. viciaba [bi.θjá.βa] ‘s/he vitiated’) which occur in

Peninsular Spanish as evidence for an underlying syllabicity contrast between diphthongs and

exceptional hiatuses.8

Finally, although the production of hiatuses (at least in the case of exceptional hiatuses) is

predicted to be more variable than the production of diphthongs (Chitoran & Hualde, 2007),

some researchers have found that diphthong production is, in fact, more variable than production

of hiatuses across speakers and dialects (Macleod, 2007).

6 Note, however, that Aguilar (1999, p.64) refers to these ‘exceptional hiatuses’ with stress on the non-high vowel as ‘normal

hiatuses’ and calls hiatuses with stress on the high vowel ‘inverse hiatuses’.

7 In contrast, the similarly exceptional diphthongs which result from the diphthongization of expected hiatuses are not assumed to

contrast with these hiatuses.

8 No minimal pairs occur for this proposed contrast. The suitability of these near-minimal pairs is discussed further in Chapter 2

where the literature concerning these sequences is reviewed in more detail.

8

The apparent complexity and contradictory tendencies observed in the production of these

sequences has resulted in a large body of theoretical and experimental literature dealing with the

characterization of diphthongs, of exceptional hiatuses and of the diphthong/hiatus contrast.

Within this literature (which will be presented and reviewed in more detail in Chapter 2) three

main ideas stood out and shaped the focus of this dissertation. These are discussed below.

4 Experimental Focus and Design

The idea for this dissertation as well as its experimental focus and design were sparked by the

following three proposals arising from the existing literature on Spanish vocalic sequences.

The first proposal is that exceptional hiatuses are triggered by a combination of historic, prosodic

and morphological factors (e.g. Chitoran & Hualde, 2007). The present dissertation argues that

while these factors may contribute to the maintenance of exceptional hiatuses in Peninsular

Spanish, the source of exceptional hiatuses is found in the phonetic variation observed across

Spanish varieties in the production of diphthongs and hiatuses.

The second proposal is that much of the variation observed in diphthong and hiatus production is

rooted in articulation (Colantoni & Limanni, 2010). Inferring from acoustic data, some authors

suggest that both the tendency for hiatuses to diphthongize and the dialectal and individual

variation in the production of hiatuses can be attributed to different gestural coordination patterns

between diphthongs and hiatuses (Chitoran & Hualde, 2007). The present dissertation tests this

proposal with information gathered from articulatory data obtained with EMA (electro-magnetic

articulography: e.g. Van Lieshout, 2006).

Finally, perception studies using syllabification judgments suggest that perception of the

diphthong-hiatus contrast (as well as perception of diphthongs and exceptional hiatuses)

generally matches speakers’ production of the same contrast (Hualde & Prieto, 2002; Face &

Alvord, 2004). The present dissertation tests these observations with perception data obtained

with an AX discrimination task.

Based on the above proposals, the main hypotheses which guide the present dissertation are:

9

(i) The phonetic variation assumed to be responsible for the occurrence of exceptional hiatuses

is present in all Spanish varieties, including those varieties described as having a high

diphthongization tendency.





These hypotheses are tested in three separate but related experiments. Although each experiment

also tests its own separate set of specific hypotheses, these are all ultimately related to each other

and to the three main hypotheses of the dissertation. Two of the experiments focus on the

production of diphthongs and hiatuses and examine both their acoustic and their articulatory

properties.

The acoustics experiment aims to (i) add to existing acoustic data on vocalic sequences in

Spanish varieties, and (ii) establish that, for the Spanish variety under study, the parameters

which define diphthongs and hiatuses and distinguish them from each other (i.e. sequence

duration, transition duration and F1 and F2 frequency contours) are the same as those found for

other varieties.

The articulation experiment complements the results from the acoustics experiment and serves to

test the second hypothesis. Examining both acoustics and articulation also helps establish

whether there are any non-linearities in the acoustic-articulatory relationship of Spanish vocalic

sequences which could help explain some of the contradictory tendencies of diphthong and

hiatus (and exceptional hiatus) distribution. In addition, the experiment contributes articulatory

data on Spanish vocalic sequences and follows a tradition of experimental articulatory research

in Spanish phonology (e.g. Romero, 1995; Recasens, 2002; Martínez Celdrán & Fernández

Planas, 2007; Colantoni & Kochetov, 2010).

The focus of the final experimental chapter is on the perception of diphthongs, hiatuses and

exceptional hiatuses in Spanish. More specifically, the chapter tests the link between variation in

production and variation in perception of these sequences. The chapter also contributes to

existing perception studies of Spanish vocalic sequences by using a different experimental

methodology than what has been traditionally employed.

10

One final component of the present dissertation motivated by existing literature on Spanish

vocalic sequences was the choice of Spanish variety to study. The next sections will provide

more detail on this aspect of the study.

4.1 Dialect and Participant Selection

Mexican Spanish was selected as the variety for this study for a couple of reasons. First, much of

the existing literature (both theoretical and experimental) on Spanish vocalic sequences is based

on Peninsular, and to a lesser extent, Argentine varieties. A study of Mexican Spanish adds to the

existing literature experimental data and insights from the Spanish variety with the most speakers

(Lope Blanch, 1996). The main reason for selecting Mexican Spanish, however, is that it is

considered a variety with a very advanced tendency towards diphthongization (Lope Blanch,

1996; Garrido, 2008). As such, it is not a variety of Spanish normally associated with the

production of exceptional hiatuses. For example, this variety frequently diphthongizes sequences

of two non-high vowels by gliding and raising the highest member of the pair, as in in teatro

[te.á tɾo] > [tjá.tɾo] and toalla [to.á ʝa] > [twá.ʝa]. In fact, a widespread use of such diphthongized

forms is reported for Mexican Spanish (Lope Blanch, 1996, p. 82; Garrido, 2008, p. 41), even

among “educated” speakers. This diphthongizing characteristic makes Mexican Spanish ideal for

testing the first hypothesis of this dissertation, as stated above.

Participants were ten adult female native speakers of Mexican Spanish, henceforth referred to as

AA, AM, AN, CG, DH, KR, LG, LL, MM, and MV. The rationale for including only female

participants in the study was to control for gender variation in production due to vocal tract size.

To ensure homogeneity (and thus reduce variation due to extra-linguistic factors) in the group,

the participants were all from similar educational backgrounds and ages. In addition, they all

spoke a similar variety of Mexican Spanish, specifically the variety spoken in Mexico City and

surrounding areas, where diphthongization is reportedly widespread across economic and

educational levels (Garrido, 2008, p. 42). None were from southern parts of Mexico where

diphthongization is thought to be somewhat less widespread (Lope Blanch, 1996). They ranged

in age from 23 to 34 years and none reported any history of language, speech or hearing

problems. All were university educated and had spent less than three years in an English-

speaking environment.

11

The participants were recruited through notices posted throughout the University of Toronto

campus and at various private English-language schools surrounding the university campus area.

All the participants but MM were in Canada briefly for periods ranging from 3 to 6 months and

were enrolled in English classes at local private schools. MM had recently completed a MSc. and

would be staying in Canada as a resident. None had any training in phonetics or phonology and

none was aware of the purpose of the study. They were compensated for their participation.

5 Dissertation Outline

The above sections have briefly presented the linguistic variables under study as well as their

associated research questions and theoretical foundations. They have also provided a rationale

for the selection of Mexican Spanish as the Spanish variety at the focus of the study. The

remainder of the dissertation is structured as follows. In Chapter 2, a selection of theoretical and

experimental studies focusing on vocalic sequences for Spanish as well as for other Romance

and non-Romance languages are reviewed.

The experimental portion of the dissertation starts with Chapter 3 (acoustics) followed by

Chapter 4 (articulation) and Chapter 5 (perception). For each of these three experimental

chapters specific research questions and hypotheses are formulated and tested. In each of the

three experimental chapters the methodological and statistical techniques unique to each

experiment are also described and any issues related to these techniques are discussed. Finally, in

each of these three chapters, the experimental results are presented, discussed and evaluated

against the specific hypotheses of the chapter.

In the final chapter, Chapter 6, a general discussion is provided for all three experiments with the

purpose of unifying and evaluating their results against the main objectives and assumptions of

the study. A proposal is made for continued research on the acoustic and articulatory properties

of VV sequences and on the production-perception link in these sequences. The inclusion of

additional varieties of Spanish in future research is also emphasized.

12

Chapter 2 Literature Review

1 Introduction

There is no shortage of literature on vocalic sequences. These sequences, especially diphthongs,

have been examined from a theoretical standpoint, from an experimental perspective and from a

combination of the two. Both the synchronic patterning of these vocalic sequences and their

historical development have been considered. Studies have looked at these sequences in specific

languages (e.g. Salza, 1988; Marotta, 1988 and Van der Beer, 2006 for Italian; Carreira, 1988;

Harris, 1989; Aguilar, 1999 and Garrido, 2007 for Spanish; Lehiste, 1967 for Estonian; Gay,

1968, 1970 and Bond, 1978 for English), within groups of related languages (e.g. Peeters, 1991

for Germanic languages; Sánchez-Miret, 1996 and Recasens, 2004 for Romance languages) and

cross-linguistically (e.g. Lindau et al., 1990; Sánchez-Miret, 1998; Sands, 2004; Nevins &

Chitoran, 2008). Despite this genuine wealth of research, many questions about such sequences

remain unanswered. These questions come up over and over again and concern even the most

basic facts about the production and perception of these sequences, many of which are still not

agreed upon and which, according to some authors, may turn out to be largely language specific

(e.g. Lindau et al., 1990; Peeters, 1991). Ultimately, any answers offered to these questions

probably depend largely upon the particular language or languages being studied, the theoretical

assumptions underlying the study, the experimental methodology employed and possibly even

the choice of sequences included in the investigation.

The present chapter reviews some of the seminal literature on the topic of vocalic sequences and

is organized as follows. In §2, a sampling of important theoretical studies for Spanish and other

languages will be examined. In §3, the experimental literature, both for production and

perception will be reviewed and §4 closes the chapter with some brief concluding remarks.

It quickly becomes obvious in this review that vocalic sequences are difficult to characterize,

both phonetically and phonologically. Part of this difficulty undoubtedly arises from the fact that

any discussion of vocalic sequences invariably involves addressing the difference between

vowels and glides. This task is complicated because glides represent a transitional class of

segment. That is, they straddle the border between vowels and consonants (as evidenced from

13

their being variously described as semiconsonants or semivowels) and can pattern with either

category, depending on the language and/or phonetic context (e.g. Padgett, 2008; Nevins &

Chitoran, 2008). Thus, it comes as no surprise that most of the studies reviewed here are neither

purely theoretical nor purely experimental. Experimental studies look to phonology either for

underlying assumptions (whether these are stated or simply implied) or for explanations of the

experimental results when these results do not reveal what was expected or are not fully

interpretable. In turn, theoretical studies reference experimental results in their phonological

characterization of vocalic sequences (e.g. Marotta, 1988; Nevis & Chitoran, 2008). In addition,

the production of vocalic sequences may be subject to varying degrees of individual and dialectal

variation (e.g. Garrido, 2007; Hualde et al., 2008; Colantoni & Limanni, 2008), adding another

layer of complexity to their characterization.

2 Theoretical Approaches to Vocalic Sequences

Theoretical studies of diphthongs and vocalic sequences in general have been concerned with

different questions depending on the language or language group being studied and the types of

vowels and vocalic sequences these languages have. Because of such differences, this section is

organized according to language and language groups. In §2.1 we begin by looking at studies

pertaining exclusively to Spanish or in which Spanish figures prominently since this is the

language which is the focus of the present investigation. We then turn to other languages in the

Romance family in §2.2 since these often share a similar theoretical focus and are thus directly

relevant to this study. Finally, theoretical studies which focus on non-Romance languages are

reviewed in §2.3. Here we examine the differences and similarities in the types of theoretical

questions being asked and relate the observations and conclusions to the present study.

2.1 Spanish

As described in Chapter 1(§3), sequences of two vowels in Spanish may be syllabified within a

single syllable to form a diphthong (a glide-vowel, GV, sequence) or in two separate syllables to

form a hiatus (a vowel-vowel, VV, sequence). Examples of the types of diphthongs and hiatuses

possible in Spanish are given in Chapter 1 and recapped in (1) and (2) below, with some

additional examples:

14

(1) Hiatuses

a) two [-high] vowels (/a e o/):

fea [fé.a], ‘ugly-fem.sing.’

teatro [te.á.tɾo] ‘theatre’;

toalla [to.á.ʝa], ‘towel’

VV: fealdad [fe.al.ðáð] ‘ugliness’

b) stressed [+high] vowel (/í ú/) and

unstressed [-high] vowel (/a e o/):

í/úV: frío [fɾí.o], ‘cold-masc.sing.’;

púa [pú.a], ‘spine,thorn’

Ví/ú: maíz [ma.ís] ‘corn’;

baúl [ba.úl] ‘trunk’

(2) Diphthongs (Gliding Rule: an unstressed high vocoid next to a different vowel is

realized as a glide: Hualde 2005)

a) Rising (GV)

j/wV: diente [djén.te], ‘ tooth’;

duelo [dwé.lo], ‘duel’

b) Falling (VG)

Vj/w: peine [péj.ne], ‘comb’;

neutro [néw.tɾo], neutral’

On the surface, this syllabification appears fairly straightforward (as long as stress assignment is

known beforehand) and minimal pairs such those in (3) below (repeated from Chapter 1) suggest

that high vowels (in hiatuses) and their corresponding glides (in diphthongs) are in

complementary distribution.

(3) GV sequence VV sequence

varias [vá.ɾjas] ‘various-fem.’ varías [va.ɾí.as] ‘you vary’

amplio [ámpljo] ‘broad/wide’ amplío [amplí.o] ‘I broaden/widen’

continuo [kon.tí.nwo] ‘continuous’ continúo [kon.ti.nú.o] ‘I continue’

Complications arise, however, when speakers diphthongize expected hiatuses (in particular those

consisting of sequences of non-high vowels, as in 1a) or produce the expected diphthongs in (2)

as hiatuses. The former phenomenon results in words such as teatro and toalla (from (1) above)

being pronounced as [teá.tɾo]/[tjá.tɾo] and [toá.ʝa]/[twá.ʝa], respectively, instead of with the

expected hiatus. This diphthongization tendency is observed (to different degrees) across Spanish

varieties and has been described as conditioned by position in the word, proximity to stress,

speech style and/or rate and frequency of usage of lexical items (Alba, 2006; Garrido, 2007,

2008). That is, diphthongization is more likely when the sequences occur in non-initial and/or

stressed syllables (Garrido, 2008), in less formal speech style and/or faster speech rate (Garrido,

2007) and when they involve frequently used words (Alba, 2006). In addition, diphthongization

is conditioned by social factors in that its occurrence may be stigmatized in some dialects

15

varieties (e.g. Peninsular Spanish: Hualde et al., 2008; Andean variety of Colombian Spanish:

Garrido, 2007) but largely accepted in other varieties (e.g. Mexican Spanish: Garrido, 2008;

Caribbean variety of Colombian Spanish: Garrido, 2007). In any case, diphthongization of

expected hiatuses is highly variable inter and intra dialectally as well as at the level of individual

speakers (Alba, 2006; Garrido, 2008; Hualde et al., 2008). Importantly, in the phonological

literature, words which may be produced with these exceptional diphthongs are not considered to

be lexically marked. Rather, they are generally handled through a post-lexical rule, such as the

following Post-Lexical Contraction Rule given in Hualde et al. (2008, p. 1908):

(4) Post-Lexical Contraction Rule: V.V VV

The second phenomenon occurs when speakers produce a word like piano piano ‘piano’ with a

hiatus ([pi.áno]) rather than with the expected diphthong ([pjá.no]). As with the diphthongization

of expected hiatuses, the production of exceptional hiatuses is conditioned by various factors.

These include etymological, prosodic as well as morphological triggers (e.g. Chitoran & Hualde,

2007). For example, exceptional hiatuses tend to occur word-initially and in stressed syllables (as

in the word piano above). They also tend to occur in the presence of morphological boundaries

(as in bienio, ‘2-year period, biennum’ which would be produced as [bi.é.njo] rather than the

expected [bjé.njo]: Hualde, 2005). Finally, they are more likely to occur in words which had

heterosyllabic vocalic sequences in Classical Latin (as in cliente, ‘client’ from Latin CLIENS

produced as [kli.én.te] rather than as [kljén.te]. In contrast to the widespread diphthongization

tendency, however, the production of these exceptional hiatuses is observed mainly in Peninsular

Spanish varieties. In addition, exceptional hiatuses are considered by many authors to contrast

with diphthongs (e.g. Harris & Kaisse, 1999; Hualde & Prieto, 2002; Hualde, 2005; Chitoran &

Hualde, 2007). These authors point to the existence of near-minimal pairs (e.g. from Hualde,

2005: duelo [dwé.lo] ‘duel’ vs. dueto [du.éto] ‘duet’) in Peninsular Spanish as evidence for an

underlying syllabicity contrast between diphthongs and exceptional hiatuses. They maintain that

this contrast requires lexical marking of vocoids [i, u] which are expected to surface as glides [j,

w] but which surface as syllabic nuclei, in violation of (2) above. In relation to this, the

occurrence of exceptional hiatuses has been used as an argument both in favour of (e.g. Harris,

1969) and against (e.g. Harris & Kaisse, 1999) the phonemic status of glides in Spanish.

Theoretical studies on Spanish diphthongs and hiatuses (and exceptional hiatuses) have focused

on three main issues, with discussions of syllable structure and/or stress assignment figuring

16

prominently in all three. The first issue concerns the phonemic status of glides in diphthongs and

deals with the question of whether [j] and [w] are independent phonemes (Harris, 1969) or

simply positional variants of the high vowels /i/ and /u/ (e.g. Colina, 1999; Harris & Kaisse,

1999; Hualde, 1999; Roca, 1997). The arguments used to justify the former are easily refuted by

those who advocate the latter and now form the more accepted position. These arguments and

counterarguments are covered in §2.1.1. A second issue concerns diphthong formation and

focuses on the Spanish alternating diphthongs. The question here is whether surface diphthongs

[je] and [we] arise from underlying vowels /e/ and /o/ or whether the surface vowels arise from

the underlying diphthongs. The arguments in favour of one or the other solution are discussed in

§2.1.2. A final related concern has been the syllabic representation of diphthongs and

monophthongs (and, thus, hiatuses) and whether there are any differences in the representation of

falling vs. rising diphthongs (Carreira, 1988, 1991). This is discussed in §2.1.3.

2.1.1 The Phonemic Status of Spanish Glides

The first issue concerns the status of Spanish glides in the phonology and directly relates to the

difference between a diphthong and a hiatus. In fact, it touches on the three-way distinction of

vowel vs. glide vs. consonant. This is because glides, especially the palatal glide [j], are

associated with both vowels and consonants. The argument for a phonemic distinction (e.g.

Harris, 1969) between /j/ and /i/ and /w/ and /u/ is based largely on evidence from three sources

which capitalize on the above association to different degrees and for different purposes.

First, the existence of near-minimal pairs with [j] (voiced palatal glide) and [ʝ] (voiced palatal

spirant approximant9) on one hand (example (5) below), and with [i] and [j] and [u] and [w] on

the other (example (6) below) would appear to be a strong argument in favour of the contrastive

nature of glides.

(5) deshielo [dez. ʝé.lo]10

‘I defrost’ vs. desierto [de.sjéɾ.to] ‘desert’ (Hualde, 2005)

9 Traditionally this type of segment was called a fricative and often represented by the symbol [y] (e.g Navarro Tomás, 1926).

Some authors continue this tradition (e.g. Borzone de Manrique & Massoni, 1981; Harris & Kaisse, 1999). However, Martinez

Celdrán (2004, 2008) prefers the symbol [ʝ] and uses phonetic data to argue that [ʝ] generally lacks the turbulent noise associated

with true fricatives (although it may be more noisy in emphatic pronunciations) and thus is more properly called a spirant

approximant. Here, we follow Martinez Celdrán in both the use of symbol and in its description.

10 Orthographic <h> is not pronounced in Spanish.

17

(6) vaciaba [baθi.áβa] ‘s/he emptied’ vs. viciaba [bi.θjá.βa] ‘s/he vitiated’

sueco [su.é ko] ‘Swedish’ vs. zueco [θwé. ko]11

‘wooden clog’ (Harris & Kaisse, 1999)

However, closer inspection of both sets of examples casts doubt on their usefulness as evidence

for the phonemic status of glides. First, the difference in syllabification for the two words in (5),

points to a difference in their morphological structure. Specifically, in deshielo, there is a

morpheme boundary (the word is composed of des ‘negative prefix’+ hielo ‘ice’) which places

the more consonantal [ʝ] in onset position where it triggers a process of voicing assimilation of

the preceding coda [s]12

. In desierto, on the other hand, the glide [j] is not preceded by a

morpheme boundary and is thus inside the syllable nucleus. Whitley (1985: 369), for instance,

argues that cases where the supposed contrast occurs in medial position do not provide sufficient

evidence of a phonemic distinction between [j] and [ʝ] since the different realizations are

predictable from syllable structure. In fact, the same examples are used in Harris & Kaisse (1999,

p. 119) to argue that neither the glides nor their more consonantal counterparts are phonemic in

Spanish (i.e. they are merely surface variants of an underlying vowel /i/ or /u/). These authors

argue that a surface contrast such as that observed in (5) appears only as a direct result of the

syllable position of /i/. When /i/ occurs in onset position as in the first word, it is subject to some

degree of consonantalization in the absence of a more appropriate or typical consonantal onset.

Conversely, when /i/ occurs in pre-vocalic nuclear position, as in the second word, it surfaces as

a glide. The examples in (6) seem to suggest, on the other hand, that the glides [j w] contrast with

the vowels [i u]. However, this argument rests on the assumption that these types of near-

minimal pairs are the norm for Spanish speakers. In fact, in these examples, the hiatus

realizations of vaciaba and sueco are ‘exceptional’ and are arguably not the typical realization of

/iV/ and /uV/ for most speakers outside of Peninsular Spanish varieties. Even for those dialects

and speakers where the contrasts in (6) are found, it can be argued that they are not phonemic

(Harris & Kaisse, 1999). We return to the subject of exceptional hiatuses as an argument for the

phonemic status of glides later in this section.

11 Orthographic <z> corresponds to /θ/ in those dialects of Spanish (i.e. Peninsular) where exceptional hiatuses are reported. In all

other Spanish dialects orthographic <z> corresponds to /s/

12 In some dialects, the voicing of /s/ is a clue to its syllabification as a coda consonant since only /s/ in coda position undergoes

voicing. It is also a clue to the consonantal status of [ʝ] since only voiced [+consonantal] segments (i.e. obstruents and sonorants)

trigger this voicing in Spanish, while glides and vowels do not. In dialects which aspirate coda /s/ to [h], aspiration rather that

voicing serves as the diagnostic (Harris & Kaisse, 1999, p. 59).

18

The second argument for a phonemic interpretation of glides comes from a three-syllable stress

assignment window, an often discussed phenomena in Spanish. In short, this window refers to

the observation that in Spanish, primary stress cannot be placed any further than the third (or

antepenultimate) syllable nucleus from the end of a word. The argument involving glides comes

about as a result of rule ordering analyses such as the one presented in Harris (1985) who

assumes that since “only stressed vowels diphthongise, the rule(s) of stress placement must apply

before the rule(s) of diphthongisation” (p. 33). The problem occurs in words such as terapéutiko

/te.ɾa.péu.ti.ko/ ‘therapeutic’ (Colina, 1999 p. 131) which should not be possible since the stress

is on the fourth vowel from the end, thus violating the three-syllable window (which is otherwise

confirmed by the data: for example, a diphthong in the penultimate syllable will block

antepenultimate stress, as in Venez[wé]la ‘Venezuela’ , not *Venéz[we]la, Harris, 1987, p. 32-

33). Such words suggest that it is diphthongization which should precede stress assignment,

leaving a ‘paradox’ situation. Harris suggests that what appears to be the fourth vowel from the

end is in reality the third vowel since the [u] is underlyingly the glide /w/. Therefore, stress is

assigned to the vowel /e/ in the antepenultimate syllable and does not violate the three-syllable

window after all. Carreira (1988) proposes that the paradox can be handled differently, namely

by ordering syllabification before stress assignment and then applying a resyllabification rule to

that output. However, these three-syllable window violations are only problematic in derivational

phonology. In Optimality Theory (OT) accounts which focus on surface forms, there is no

violation at all (Colina, 1999, p. 131) since the three-syllable window applies to surface forms

and it is the glide [w] which appears in the surface form.

A final argument for the phonemic status of glides involves the presence of exceptional hiatuses

in some dialects of Spanish. Harris (1969), for example, claims that the verbs guiar ‘to guide’

and piar ‘to chirp’ form a near-minimal pair in which the former is pronounced consistently as

monosyllabic [gjár] and the latter as disyllabic [pi.ár]. Harris (1969, p. 126-127) attributes the

difference to a difference in the underlying representation of each verb, where guiar has a glide

and piar a vowel (at least in some dialects) but such an explanation is ultimately unsatisfactory.

An OT analysis of these exceptional hiatuses is offered by Colina (1999) who also accounts for

the dialectal and individual variation associated with analogical forms An example of analogical

exceptional hiatus would be the <ia> sequence in diario ‘newspaper, daily’ which may be

realized as [di.á.ɾjo] rather than the expected [djá.ɾjo] through analogy with día [dí.a] ‘day’.

19

Colina (1999) handles this variation by way of Correspondence Theory and identity constraints.

Specifically, she proposes that speakers who realize such words with hiatus have established a

correspondence relation between certain lexical items (e.g. between diario and día) and are

making use of an IDENTσ constraint which requires that /i/ have the same syllabic role in diario

as in its correspondent día (i.e. it must be in a separate syllable). However, the matter of these

exceptional hiatuses is complicated and appears to be conditioned by other factors, not just

analogy (as discussed above, these include morphological boundaries, position in the word,

proximity to stress, and sequence etymology). For example, there are words which are described

as being consistently produced with an exceptional hiatus but which have no analogical

counterpart with a hiatus. One such word is diablo ‘devil’ (cited in Navarro Tomás, 1926; Harris

& Kaisse, 1999; Hualde, 2005, among others). Similarly, there are also words with clear

analogical relationships but which are cited as occurring as diphthongs. In the data from Harris

(1969) cited above, for example, guiar [gjár] and piar [pi.ár] both have related words with

hiatus: guía [gí.a] ‘guide-N’ and pía [pí.a] ‘chirps’, respectively. Yet only piar is said to have an

exceptional hiatus.

Harris & Kaisse (1999) use distribution data from Argentine (AR) and Castilian Spanish (SC) to

offer a single rule-based analysis to refute the argument of a phonemic status for glides. They

show how underlying /i/ and /u/ surface as either glides in diphthongs or vowels in hiatus. They

propose that “[j] and [w] are derived from /i/ and /u/, respectively, as are peak [i] and [u] in

simple nuclei’ (p. 124). Exceptional hiatus is handled through lexical marking where [i u] are

marked as syllabic [i. u.] to allow them to surface as hiatuses rather than diphthongs. A series of

sequentially-ordered rules then produce the appropriate surface representation. Similarly, they

propose that “all of [i j y ʝ ž ǰ] are realizations of [-consonantal] segments in underlying

representations” (p. 119). In other words, they are all surface variants of /i/. Any derived

consonantal features are supplied by a rule of Consonantalization which applies to onset /i./ and

give rise to [ʝ] and its variants13

. In Harris & Kaisse (1999) dialectal and individual variation in

the production of exceptional hiatuses is handled through differences in the application of a

13 An additional rule of Coronalization is given for AR to produce the coronal fricative [ʒ](symbolized as [ž] by these authors)

which occurs in onset position for this variety (in words with orthographic <y>). This rule applies prior to PreD in AR and

prevents neutralization of syllable–initial [j] with a denuclearized /i./ thus allowing for a surface contrast between yate [ʒá.te]

‘yacht’ and hiato [ʝá.to] ‘hiatus’ (Harris & Kaisse, 1999, p. 139).

20

Prevocalic DeNuclearization (PreD) rule. This rule turns an underlying /i.V/ sequence into [jV].

The authors propose that PreD applies optionally and only postlexically (i.e. at the phrasal level)

in SC but lexically (and presumably not optionally) in AR (Harris & Kaisse, 1999, p. 177-178).

This proposal is illustrated with the following hypothetical derivation for the word vaciaba from

(6) above, for both AR and SC.

(7) Hypothetical derivations based on analysis in Harris & Kaisse (1999, p. 170)

AR SC

Underlying representation /basi.aba/ /baθi.aba/14

Word domain (lexical)

syllabification [ba.si.a.βa] [ba.θi.a.βa]15

stress assignment [ba.si.á.βa] [ba.θi.á.βa]

PreD [ba.sjá.βa] ------------

Output [ba.sjá.βa] [ba.θi.á.βa]

The above derivation shows a dialectal difference in the output: a diphthong realization for AR

and a hiatus realization for SC. However, the application of the optional phrasal level PreD rule

for SC to the above output then gives us the alternate surface form [ba.θjá. βa] for this variety as

well. Thus, SC individuals may choose to apply this rule and optionally realize exceptional

hiatuses as diphthongs. This proposal would seem to explain both dialectal and individual

variation in the production of these hiatuses. Nevertheless, the existence of such variation raises

the question of whether it is necessary to assume an underlying syllabicity contrast at all. First,

Harris & Kaisse (1999) concede that the vaciaba-viciaba or sueco-zueco type of contrasts are

subject to individual variation even in the Peninsular Spanish variety with which they are

associated (as do other authors, e.g. Hualde & Prieto, 2002; Cabré & Prieto, 2006; Chitoran &

Hualde, 2007). Even for those individuals who produce them, these hiatuses are generally limited

to strong positions within the word (Chitoran & Hualde, 2007) and may be affected by speech

style and rate (Aguilar, 1999). Finally, these contrasts are not generally attested outside of the

Peninsular variety. In short, there is little evidence of a strong syllabicity contrast and

diphthongization appears to be the predominant tendency in Spanish. Whitley (1985), for

14 In varieties of Peninsular Spanish orthographic <c> followed by a front vowel corresponds to the phoneme /θ/.

15 Intervocalic /b/ in Spanish is generally realized as an approximant [β].

21

example, likens the hiatus pronunciation of an /iV/ sequence to a kind of ‘recessive’ trait in

Spanish. He maintains that the idiolectal variation, instability and limited distribution associated

with this ‘hiatophilia’ (Whitley, 1985, p. 376) are due to a path of historical erosion of an [iV] ~

[jV] contrast which continues in the present as more and more words join the diphthong

category.

Overall then, the phonemic status of glides in Spanish is not completely clear, at least if we

consider only the above studies. It is not even clear whether this determination is all that crucial

for phonological theory (Padgett, 2008). Perhaps a better approach would be to loosen the

definition of a phonological category so that it is less discrete and fuzzier around the edges. This

proposal is put forth by Hualde (2004) who suggests that glides may be more or less vocalic or

consonantal “depending on the dialect, the style and the speaker” (Hualde, 2004, p. 20) to the

extent that the category boundaries between vowel and glide, in other words between diphthong

and hiatus, will be different for any given speaker. A related approach is taken by Nevins &

Chitoran (2008). These authors attempt to reconcile the cross-linguistic data which shows that

the glides [j w] may pattern either with vowels or consonants. The reason for this, they argue, is

that glides are not represented phonemically as either consonants or vowels. Rather, they differ

featurally from both. Specifically, they possess both consonantal and vocalic features and are

best represented by a combined feature designation of [±vocalic] which gives glides a

constriction degree which is unlike that of vowels or consonants. In addition, these authors cite

articulatory data from Gick (2003-reviewed in §3, this chapter) which suggests that English /j/

consists of both a vocalic gesture (Tongue Dorsum) and a consonantal gesture (Tongue Tip).

They interpret this experimental data as supporting their featural theory and expand on it to

propose that glides are assigned two separate articulators, one vocalic ([Dorsal]) and one

consonantal ([Coronal] for /j/ and [Labial] for /w/. These representations are offered as

explanations as to why /j/ can alternate with a coronal fricative [ʒ] in Argentine Spanish and a

dorsal stop /k/ in Cypriot Greek, for example. Variation in these alternations may arise as a result

of the relative magnitude of each gesture in a particular language (Nevins & Chitoran, 2008, p.

1994). In a similar vein, Padgett (2008) also maintains that glides and vowels (and thus

diphthongs and hiatuses) differ featurally in degree of constriction, with the difference in

syllabicity being a simple consequence of the featural differences (Padgett, 2008, p.1944).

22

2.1.2 Alternating Diphthongs (‘los diptongos alternantes’) in Spanish

As outlined in Chapter 1, diphthongs in Spanish may have resulted from Latin heterosyllabic

sequences (ITALIA > [i.tá.li.a] > [i.tá.lja] ‘Italy’) or from the deletion of intervocalic consonants

(REGINA > [re.í.na] > [réj.na] ‘queen’). Another source is the Latin short mid vowels Ĕ and Ŏ

(/ɛ/ and /ɔ/ in Vulgar Latin). These vowels diphthongized in stressed syllables in some Romance

languages, including Spanish, producing unstressed monophthong~stressed diphthong

alternations such as the following16

:

(8) [e] ~ [jé]: pensar [pen.sár] ‘to think’ ~ pienso [pjén.so] ‘I think’

[o] ~ [wé]17

: contar [kon.tár] ‘to count/tell a story’ ~ cuenta [kwén.ta] ‘he/she

counts/tells a story’

The importance of these sequences to the present dissertation arises from: (i) the fact that this

monophthong~diphthong alternation, like the diphthong-hiatus contrast, is linked to stress

assignment; and, (ii) the prediction that diphthongs historically related to Latin /ɛ/ and /ɔ/ are

without exception produced as diphthongs and may never be produced as exceptional hiatuses

(Hualde, 2005; Chitoran & Hualde, 2007). That is, they never violate the Gliding Rule in (2).

The two competing derivational approaches regarding these alternations involve

monophthongization (Carreira, 1991) and diphthongization (e.g. Harris, 1985; Harris & Kaisse,

1999). The monophthongization approach in Carreira (1991) uses a complicated system of

constraint violations and repair strategies to achieve the correct surface structure. It assumes that

the diphthongs, rather than the simple vowels, are underlying and that the nuclear vowels of the

diphthongs are underspecified. According to Carreira (1991), the Spanish diphthongs [je] and

[we] are derived from underlying sequences consisting of a [+high] vowel and an empty V slot

corresponding to a [-high vowel]: iV (ie) and uV (uo), respectively. These sequences, following

rules of syllabification, default feature assigment and contraction yield the following

intermediate sequences which are associated to a single V slot in the syllable: {je} and {wo}.

However, at this stage in the derivation, {wo} violates a presumed “ban in Spanish on sequences

of tautosyllabic segments that are [+round, +back] (Carreira, 1991, p. 419). According to

16 Modern Spanish does not have /ɛ/ and /ɔ/ in its phonemic inventory.

17 The historical development of this diphthong in Spanish occurred as follows: /wɛ/ > /wo/ > /we/ (Carreira, 1991, p. 438;

Penny, 2002, p.52).

23

Carreira (1991), “this violation is resolved by eliminating the place of articulation features of the

nuclear vowel” (p. 438) and then replacing these features with the Spanish default vowel /e/,

producing the surface form [we]. Because {je} does not violate any constraints, it surfaces as [je]

without undergoing any changes. In the absence of stress, the first element of the diphthong

undergoes deletion and only the mid vowel is left.

Harris (1985), on the other hand, proposes that the underlying mid vowels /e o/ undergo a rule of

diphthongization which applies only in stressed positions (thus reiterating his point of view that

stress assignment precedes diphthongization). The problem of why /o/ [we] instead of [wo]18

is handled through the application of a default rule which follows the diphthongization rule and

assigns a default value of [e] to any prosodic position “that can be occupied by a vowel but in

fact has no vowel feature attached to it” (Harris, 1985, p. 37). Finally, a High-glide rule yields

the necessary glides. Thus, the following steps are assumed in the derivation of the diphthongs:

(9) oV→oe→we; eV→ee→je

Harris and Kaisse (1999) also support the diphthongization hypothesis and suggest that the

underlying mid vowels /e o/ surface as the diphthongs /je/ and /we/ through a diphthongization

rule which follows the application of stress assignment and syllabification rules (Harris &

Kaisse, 1999, p. 138). As with the vowel-glide alternation discussed earlier, these types of

alternations are handled through lexical marking of the relevant underlying vowels (/e! o!/ are

lexically marked to surface as diphthongs whereas /e o/ are not).

Difficulties with these rule-based approaches arise when we observe that the diphthong-

monophthong alternations (like the vowel-glide contrast in diphthongs and hiatuses) are not

entirely predictable (Eddington, 1998, 2004). For example, stressed [e] and [o] in Spanish are not

always realized as diphthongs, as in (10).

(10) [e] ~ [é]: pesar [pe.sár] ‘to weigh’ ~ peso [pé.so] ‘I weigh’

[o] ~ [ó]: coser [ko.sér] ‘to sew’ ~ cose [kó.se] ‘he/she sews’

Similarly, diphthongs may occur in unstressed syllables, as in (11).

18 Limanni (2008) suggests a perceptual explanation based on coarticulation for the [wo] > [we] historical change in Spanish.

Such an explanation would call into question the need for a synchronic rule-based account (Blevins, 2004).

24

(11) [jé] ~ [je]: viejo [bjé.xo] ‘old man’ ~ viejito [bje.xí.to] ‘little old man’

[wé] ~ [we]: cuento [kwén.to] ‘story’ ~ cuentista [kwen.tís.ta] ‘story-teller’

In derivational accounts, an absence of lexical marking on the underlying vowels is assumed to

explain those cases where the mid vowels fail to diphthongize (e.g. Harris & Kaisse, 1999). The

presence of diphthongs in unstressed syllables, on the other hand, has been handled through the

cyclic application of a stress rule which first triggers diphthongization and then moves on to

another syllable (Halle, Harris & Vergnaud, 1991). Eddington (1998, 2004), however, challenges

the rule-based accounts of the diphthong–monophthong alternation in Spanish with experimental

evidence that the alternation is a semi-productive, gradient process influenced by the presence of

certain suffixes and by analogy. Eddington (1998, 2004) further suggests that the alternation is

not triggered by stress since stress, in his view, is not entirely predictable and is stored as an

inherent part of each lexical item.

2.1.3 The Syllabic Representation of Spanish Diphthongs

The issue of how Spanish diphthongs are to be represented in terms of syllable structure also

touches on the difference between diphthongs and monophthongs. However, an additional issue

which turns up is the syllabic difference between rising diphthongs of the form GV and falling

diphthongs of the form VG. The difference has been proposed to be one of syllable weight or

moraic structure. According to moraic theory (Kenstowitz, 1994, p. 428-429; Kager, 1999,

p.147), morae (μ) are the weight-bearing units which make up the syllable (σ). Syllable weight

can be attributed to how many morae are contained within a syllable nucleus. Within this theory,

heavy syllables are bimoraic (μμ) while light syllables are monomoraic (μ). Short vowels differ

from long vowels in that the former are monomoraic and the latter are bimoraic, with two morae

attached to one vocalic position, as represented below (adapted from Kager, 1999, p. 147;

Kikuchi, 1997, p.41):

(12) a. Short Vowels (light syllable) b. Long Vowels (heavy syllable)

[V] [V:]

σ σ V

μ μ μ yt V V

25

While the above structures for simple vowels are generally straightforward (assuming one

accepts syllable and moraic theory), the moraic structure of diphthongs is more complex. The

following two different moraic structures have been proposed for diphthongs (adapted from

Rosenthall, 1994, p. 21):

(13) a. [V1V2] b. [V1V2]

σ σ

V

μ μ μ

V

[V1 V2] [V1 V2]

The first structure (13a) represents diphthongs as monomoraic, where a single mora is linked to

two different vocalic positions. The second structure (13b) represents diphthongs as bimoraic,

where each mora is associated with a different vocalic position. In Spanish, there is phonotactic

evidence of a monomoraic structure, at least for rising diphthongs. First, GV diphthongs can

occur in both open (CV) and closed (CVC) syllables in this language. In addition, Spanish

contains sequences of the type Consonant-Liquid-Glide-Vowel (as in the first syllable of pliegue

[pljé.ge] ‘fold’ and prieto [pɾjé.to] ‘dark’). Syllabifying these glides as part of the onset would go

against the observation that most languages do not allow three consonants in onsets (unless one

of them is /s/). Spanish onsets, in fact, may contain at most two consonants and these are

restricted to combinations of either /f/ + Liquid or Stop + Liquid (Hualde, 2005). This type of

evidence has led to the assumption that in this language rising diphthongs (GV) are best

represented as monomoraic (Carreira, 1991, 1992; Rosenthall, 1994; Holt, 1997). Carreira (1991,

1992) further observes that there are distributional asymmetries between GV and VG

diphthongs. Falling diphthongs, unlike rising diphthongs, for example, may only appear in an

open syllable, as in peine, [péj.ne] ‘comb’. In support of this asymmetry hypothesis, Carreira

(1992) also cites phonetic evidence regarding the duration of rising (GV) vs. falling diphthongs

(VG) which suggests that the latter are longer than the former (which are comparable in duration

to monophthongs). In fact, VG sequences are described as similar in length to VC sequences.

Thus, Carreira (1992, p. 29) proposes that based on distributional and phonetic evidence, VG

diphthongs are bimoraic while GV diphthongs are monomoraic. In fact, the acoustic evidence is

not without controversy. More recent durational data from Aguilar (1997) suggests that the

opposite is true. That is, GV sequences are in fact longer than VG sequences, in support of a

26

more ‘consonantal’ characterization for pre-vocalic glides and a more ‘vocalic’ characterization

for post-vocalic glides. This provides experimental evidence that their long-standing

nomenclature as semiconsonants when prevocalic and semivowels when postvocalic is

warranted.

2.2 Other Romance Languages

As with Spanish vocalic sequences, the notion of syllable affiliation figures prominently in

phonological studies of similar sequences in other Romance languages. Here we look at these

sequences primarily in Italian and Romanian since both these languages can be said to maintain

(albeit to different degrees) a diphthong-hiatus contrast and any analyses pertaining to these two

languages would be directly relevant to Spanish. We also briefly touch on the status of vocalic

sequences in French and Portuguese, two languages which are said to correspond to the two

extremities of the Romance diphthong-hiatus continuum: French is said to have no hiatuses

while Portuguese is characterized as having no diphthongs (e.g. Chitoran & Hualde, 2007).

2.2.1 Italian

Italian, like Spanish, has both falling diphthongs and rising diphthongs. The latter category also

includes the diphthongs inherited from Latin short mid vowels Ĕ and Ŏ. In Italian, as in Spanish,

these appear mainly in stressed syllables, although analogical levelling may place them in

unstressed contexts in some cases (Van der Beer, 2006). They generally alternate with the

corresponding short vowels in unstressed positions and thus are called mobile diphthongs (i

dittonghi mobili) in this language (e.g. Van der Beer, 2006). In Italian, unlike in Spanish,

however, these mobile diphthongs may not appear in closed syllables (examples from Van der

Beer, 2006, p. 53)

(14) [ɛ] ~ [jɛ sederò [se.de.ró] ‘I will sit’ ~ siedo [sjɛ do] ‘I sit’

[ɔ] ~ [wɔ movimento [mɔ.vi.mɛn.to] ‘movement’ ~ muovo [mwɔ vo] ‘I move’

Also like Spanish, Italian has both a palatal glide [j] and a velar glide [w]. However, there have

been arguments put forth that, in reality, only /j/ has autonomous phonological status (Marotta,

1988). According to Marotta (1988), the syllable structure of jV sequences differs from the

structure of wV sequences. Namely, the latter are subject to more stringent distributional

restrictions. For example, in word-initial position [j] may combine with any vowel while [w]

27

may only appear in [wɔ]. Also, in word-internal positions, diphthongs with [j] and any other

vowel may be preceded by almost any class of consonants (except palatal fricatives and

affricates). On the other hand, only [wɔ, wo] may enjoy this combinatorial freedom. Any other

combinations of wV occur only after a velar stop [k g] and thus are more aptly considered a kind

of complex nucleus. Also, mobile diphthongs with [j] participate more readily in analogical

levelling while those with [w] are more resistant to levelling, not appearing in most cases or only

optionally in others. The examples in (14) show this asymmetry in nouns and their diminutives:

(15) Analogical levelling of [jɛ and [wɔ in Standard Italian (Van der Beer, 2006, p.121)

Noun Diminutive

piéde ‘foot’ piedíno

piétra ‘stone’ pietrína

but uómo ‘man’ ométto/omíno

uóvo ‘egg’ ovétto

Therefore, according to Marotta (1988, p. 401), the distribution facts point to the following

analysis for Italian. First, GV sequences are best described as consisting of two elements, the

initial of which belongs to the syllable onset and the second to its nucleus. Thus, if we accept a

strict definition of a diphthong as a combination of two vocalic elements sharing a single

nucleus, jV sequences in Italian are not true diphthongs. Second, only [wo, wɔ] are associated

with a complex nucleus and as such, may be said to be the only true diphthongs in Italian. Finally

combinations of [kw, gw] are syllabified as a complex onset. Van der Beer (2006, p. 92-93), on

the other hand, combines moraic theory and his own experimental durational and perceptual data

(discussed in more detail in §3 below) to propose different options for the structure of rising

diphthongs in Italian, at least the mobile kind. In his analysis, for both jV and wV sequences, the

glides are not part of the onset. He proposes instead that different moraic structures arise in

stressed syllables versus unstressed syllables: in stressed syllables, rising diphthongs (both with

[w] and with [j] are bimoraic while in unstressed syllables they are monomoraic.

Falling diphthongs, on the other hand, are always considered bimoraic (Van der Beer, 2006),

based on distributional evidence that these serve to close the syllable (for example, they may not

appear with geminates). The glide in the VG sequences is thus in coda position, in line with a

proposal by Marotta (1988). Krämer (2009) disagrees with Van der Beer’s analysis of rising

28

diphthongs arguing that Italian syllables are at most bimoraic and coda consonants are assigned a

mora. As a result, “a glide in a stressed closed syllable, as in pianta ['pjanta] ‘plant’, cannot be in

the nucleus” (Krämer, 2009, p. 99) since the presence of a coda consonant would require a

trimoraic structure which does not exist in Italian. In this view, Van der Beer’s analysis works

only for mobile diphthongs and as such loses generality.

Also like Spanish, albeit to a lesser degree (Chitoran & Hualde, 2007), Italian has a diphthong-

hiatus contrast which is maintained through stress assignment and syllabification. That is,

sequences of high vowel and non-high vowel are hiatuses when the high vowel is stressed but

diphthongs when the high vowel is not stressed. Thus, we find the following near-minimal pairs:

Laura [láw.ra] (person’s name) vs. paura [pa.úra] ‘fear’, and faida [fáj.da] ‘feud’ vs. faina

[fa.í.na] ‘stone-marten’ (Bertinetto & Loporcaro 2005: 139). Sequences of two non-high vowels

also form hiatus in Italian, as in coalizione [ko.a.li.t:sjó.ne] ‘coalition’ and stereotipato

[stɛ.re.o.ti.pá.to] ‘stereotyped’ (Bertinetto & Loporcaro, 2005, p. 139). In addition, there are

cases of exceptional hiatus in Italian, as in biennale [bi.e.n:á.le] ‘biennial’. However, the

difference between diphthong and hiatus is said to be difficult to discriminate (Marotta, 1987).

As a consequence, we find the same diphthongizing tendency as in Spanish, both with sequences

of non-high vowels and with exceptional hiatuses, as in coalizione [koa.li.t:sjó.ne] ‘coalition’,

stereotipato [stɛ.reo.ti.pá.to] ‘stereotyped’, and biennale [bje.n:á.le] ‘biennial’. As in Spanish,

the likelihood of diphthongization in these cases rises as proximity to stress decreases and speech

rate increases.

In summary, while much controversy remains as to the syllabic affiliation of diphthongs and the

status of [j] and [w] in Italian, an important observation is made by Marotta (1988) that not all

glides behave equally. Thus, in Italian, [j] may be more consonantal than [w] which has more

vocalic features. This more-or-less approach also figures in Marotta (1987) where the author

suggests that the difference between diphthong and hiatus is best looked at, not as a categorical

opposition, but as a variable continuum which ranges from monophthong on one extreme and

hiatus on the other, with diphthongs falling somewhere in between (Marotta, 1987, p. 882). This

is reminiscent of what was suggested for Spanish in Hualde (2004) and is in line with what is

proposed by Sánchez Miret (1998) in his overview of the literature on diphthongs.

29

2.2.2 Romanian

As in Spanish, Romanian diphthongs may be formed with a high glide (/j w/) or a mid-glide (/e

a/). In Romanian, however, only the latter are classified as phonological diphthongs (Chitoran,

2002; Marin, 2007). The former are regarded as glide-vowel sequences based on their

distributional and orthographic characteristics. For example, the mid vowel diphthongs ([ea] and

[oa]) may follow a complex onset consisting of an obstruent-liquid cluster but sequences of [ja]

or [wa] may not (Chitoran, 2002). In addition, it is argued that since Romanian orthography19

distinguishes between glide-vowel sequences and diphthongs, that these are phonologically

contrastive (Chitoran, 2002). The existence of minimal and near-minimal pairs such as [beá.tǝ]

‘drunk-fem.’and [bjá.tǝ] ‘poor-fem.’ (Chitoran, 2002, p. 211) also suggest that these sequences

be given a different phonological treatment. Thus, the high glides in glide-vowel sequences are

syllabified as part of the onset. In contrast, the mid glides in the diphthongs are syllabified as part

of the nucleus together with their associated vowel (Chitoran, 2002; Marin, 2007). However, the

distributional analysis is complicated by the fact that the glide-vowel sequence [wa] is relatively

infrequent and appears primarily in loan words (Chitoran, 2002, p. 208). In addition, the glide

[w] differs from [j] in that it does not appear in word-initial position and is only followed by [a].

The glide [j], on the other hand, combines freely with all vowels and appears in word-initial

position (Chitoran, 2002, p. 206-207). This points to a different status for these glides,

suggesting that, as in Italian and possibly Spanish, [j] and [w] behave differently. This

observation is supported by experimental data which finds significant acoustic and perceptual

differences between [ea] and [ja] but none between [oa] and [wa] (Chitoran, 2002). An important

observation made here is that what counts as a diphthong phonologically differs from one

language to the next.

A final point must be made about the diphthong-hiatus distinction in Romanian, since this

distinction is said to be robust in this language, even more so than in Spanish (Chitoran &

Hualde, 2007). It is claimed that the difference is predictable etymologically, since the hiatus

sequences derive either from the maintenance of Latin heterosyllabic sequences or from

19 It could be argued, however, that orthography is not the best argument for a synchronic phonological distinction since

orthographic differences may be maintained after a phonological contrast has disappeared. For example, Spanish has both

orthographic <b> and <v>, as shown in the words baca ‘luggage rack’ and vaca ‘cow’. However, both graphemes correspond to

the phoneme /b/. That is, the phonological contrast they once represented disappeared long ago (Hualde, 2005).

30

loanwords from other languages (Chitoran & Hualde, 2007). However, this applies only to the

maintenance of the contrast between [ea] and [ja] and even in these cases, production evidence

from Chitoran (2002, 2003) suggests that some speakers do not produce the prescribed hiatus,

leaning instead towards a diphthong pronunciation. Therefore, even in Romanian, the [iV] ~ [jV]

contrast may not be as robust as claimed.

2.2.3 French

French, unlike Spanish, is said to have no diphthong-hiatus contrast (Chitoran & Hualde, 2007,

p. 44-45). Specifically, in French, sequences of high and non-high vocoids result in gliding of the

first element and are consistently produced as diphthongs. The examples in (16) illustrate how

high vowels alternate with their corresponding glides when they appear next to another vowel:

(16) French high vowel-glide alternations (Tranel, 1987, p. 119)

[i]~[j]: scie [si] ‘saw-N’ ~ scier [sje] ‘to saw’

[y]~[ɥ]: tue [ty] ‘s/he kills’~ tuer [tɥe] ‘to kill’

[u]~[w]: loue [lu] ‘s/he rents’ ~ louer [lwe] ‘to rent’

Some exceptions to gliding exist when the sequences occur in one of two contexts: (i) after a

complex onset, and; (ii) in the presence of a word or morpheme boundary. In the first case,

gliding is blocked after Consonant-Liquid (CL) cluster, as in plier [pli.(j)e]20

‘to fold’, gluant

[gly.ɑ ‘sticky’, and clouer [klu.e] ‘to nail’ (Tranel, 1987, p.120). The second case is illustrated

by examples such as loua [lu.a] ‘s/he praised’ (Walker, 2001, p. 103), semi-aride [sœ.mi.a.rid]

‘semi-arid’, and si adorable [si.a.dɔ.rabl] ‘so cute’ (Tranel, 1987, p. 119). These exceptions are

subject to both dialectal (Durant & Lyche, 1999) and individual variation (Tranel, 1987).

However, the dominant tendency is diphthongization and the alternations in (16) are seen as

evidence that these GV sequences are derived from underlying VV sequences. That is, as in

Spanish, these glides are positional variants of high vowels and their occurrence is predictable.

On the other hand, French is said to differ from Spanish in having a set of phonemic glides in

addition to the derived glides above (Harris & Kaisse, 1999, p.130). This analysis is based on

differences in the phonological behaviour of glide-initial words: phonetically, there is no

20 A transitional glide ([j]) is said to appear in CLi sequences but not generally in Cly or CLu sequences (Durant & Lyche, 1999;

Tranel, 1987; Walker, 2001).

31

difference between them (Harris & Kaisse, 1999, p. 130). Specifically, the glides in some of

these words behave like onset consonants and block the processes of liaison and elision in

preceding definite articles les [le] and le [lœ] while the glides in other words pattern with vowels

and do not block these processes. This difference yields near-minimal pairs such as le whisky

[lœwiski] ‘the whisky’ vs. l’oiseau [lwazo] ‘the bird’ (Tranel, 1987, p. 117) and le yoga [lœjɔga]

‘yoga’ vs. l’iode [ljɔd] ‘iodine (Walker, 2001, p. 105). This contrast is, however, tenuous and

subject to individual variation such that, for some words, both realizations are attested: le

iambe/l’iambe ‘the iamb’ and le hiatus/l’hiatus ‘the hiatus’ (Walker, 2001, p. 106). In fact, the

words which block liaison and elision appear to belong to a class of foreign borrowings while

those with variable realizations seem to be native but arguably uncommon items If this is the

case, the distinction may not really be one of phonemic versus derived glides as much as an

example of lexical diffusion (Wang, 1969; Labov, 1994) where some words are in the process of

being assimilated to the standard patterns of liaison and elision while others lag behind. A similar

analysis is given for word-initial glides in Spanish by Whitley (1985) (see §3.3.1 in this chapter).

2.2.4 Portuguese

Portuguese is also said to not have a diphthong-hiatus contrast (Chitoran & Hualde, 2007, p. 47).

This language has a large inventory of falling diphthongs, as in pai [paj] ‘father’, boi [boj] ‘ox’,

and eu [ew] ‘I’(Azevedo, 2005, p. 29) but a hiatus realization is supposedly preferred for

sequences of high and non-high vocoids (Chitoran & Hualde, 2007). However, diphthongization

is widely attested in such sequences and is said to be subject to individual, dialectal and stylistic

variation (Silva, 1999, p. 96). For example, European Portuguese speakers may diphthongize a

sequence while Brazilian speakers may prefer to maintain hiatus (Silva, 1999, p. 96). In both

cases, an informal speaking style may also produce diphthongs (Mateus & D’Andrade, 200,

p.49; Azevedo, 2005, p. 29-31). Thus, the following words may be realized with either diphthong

or hiatus: pátria [pá.tɾi.ɐ] ~ [pá.tɾjɐ] ‘homeland’ and quieto [ki.ɛ tu] ~ [kjɛ tu] ‘quiet’ (Azevedo,

2005, p. 29). Proximity to word stress may be a conditioning factor such that diphthongization is

more likely to occur in post-tonic syllables (Chitoran & Hualde, 2007, p. 47), although some

counterexamples exist, as in gracioso [gɾa.si.ó.zʊ] ~ [gɾa.sjó.zʊ] ‘graceful, charming’ (Silva,

1999, p. 96). Overall then, even in Portuguese V-V sequences show some instability and

variation and are not immune to the same tendency towards diphthongization exhibited by

Spanish, Italian, French and Romanian.

32

2.3 Non-Romance Languages

This section briefly reviews some of the theoretical questions regarding vocalic sequences in

non-Romance languages. Specifically, we look at three Germanic languages: English, Dutch and

German. Because none of these languages has a strong diphthong-hiatus contrast, some of the

theoretical questions regarding their vocalic sequences differ from those found in the Romance

languages discussed above. For English and German, for example, a major concern has been to

identify the phonological differences between monophthongs and diphthongs. For Dutch, the

focus has been on the differences between ‘genuine’ diphthongs consisting of two vowels and

‘pseudo’ diphthongs consisting of glide-vowel sequences. However, some questions are similar

to those found in the literature on Romance languages. One such question involves the phonemic

status of diphthongs in general and glides more specifically. Related questions include whether

diphthongs are best characterized as single vocalic elements or as sequences of two vocalic

elements.

2.3.1 English

English has three falling diphthongs, /aɪ, ɔɪ, aʊ/21

, as in buy, boy and bough (Kent & Read, 2002,

p. 136). The tense mid vowels of English /e/ and /o/, as in bait and boat, are also produced with a

diphthongal off-glide and may be transcribed phonetically as [eɪ] and [oʊ] (e.g. bait [beɪt] and

boat [boʊt]). Although the latter are generally included in the diphthong category by

experimental researchers (e.g. Gay, 1968; Bond, 1978; Morrison 2009), phonologists have tried

to make a distinction between phonemic and phonetic diphthongs. Pike (1947), for example,

maintains that the two types of diphthongs are structurally different. Specifically, he claims that

phonemic diphthongs are biphonemic (i.e. behave as sequences of two phonemes) while phonetic

diphthongs are monophonemic (i.e. behave as single phonemes), albeit phonetically complex

(Pike, 1947, p. 151). His evidence includes the following: (i) phonetic diphthongs lose part or all

of their diphthongization when they are pronounced rapidly but phonemic diphthongs do not; (ii)

phonetic diphthongs lose most of their diphthongization when they occur in unstressed syllables

while phonemic diphthongs tend to maintain theirs to a greater degree (or lose less of it); and (iii)

American students of phonetics easily perceive the diphthongal nature of /aɪ, ɔɪ, aʊ/ but struggle

21 These diphthongs are variously transcribed as [aɪ, ɔɪ, aʊ], [ai, ɔi, au], and [aj, ɔj, aw].

33

to learn to recognize the glide element in [eɪ] and [oʊ]. Pike’s evidence comes from subjective

observation but there is some experimental evidence to support a different characterization for

these two types of diphthongs. Specifically, according to Lehiste and Peterson (1961) [eɪ, oʏ]

represent ‘single-target’ complex nuclei while [aɪ, ɔɪ, aʊ] are ‘dual-target’ complex nuclei. These

authors suggest that only the latter group are ‘diphthongs’ (Lehiste & Peterson, 1961, p. 276).

Additionally, English has Glide-Vowel sequences involving the palatal glide [j], as in cute [kjut],

and the velar glide [w], as in queen [kwin] (Davis & Hammond, 1995)22

. One issue concerning

these sequences is whether or not they are diphthongs. Some have suggested that only falling

diphthongs could be called ‘true diphthongs’ (e.g. Donegan, 1978) and that GV sequences

behave more like CV sequences. Donegan (1978), for example, argues that GV sequences do not

function as units but VG sequences do. First, she maintains that the glide in GV sequences does

not count in speech timing. That is, the glide forms part of the syllable onset and is not assigned

a mora. Thus, phonologically, GV is equal to V in timing. Secondly, she observes that VG

sequences behave as units in rhyming but GV sequences do not. Thus, paid [pejd] rhymes with

raid [rejd] but not with red [rɛd]. On the other hand, feud [fjud] rhymes with both mood [mud]

and mewed [mjud] (Donegan, 1978, p. 107). Other authors have found a further asymmetry

between jV sequences and wV sequences. Davis & Hammond (1995) argue, on the basis of

phonotactic patterns and evidence from Pig Latin game forms that [j] and [w] in English behave

differently in terms of phonological status. In short, the [w] in CwV sequences in English is said

to pattern like sequences in which the second element is a liquid. For example, like CL

sequences, Cw sequences are not restricted as to the following vowel (e.g. queen, quote, quack).

On the other hand, the C in these sequences must be an obstruent (never a nasal, for example). In

other words, Cw sequences form a complex onset. Therefore, such sequences are not really

rising diphthongs. On the other hand, the authors argue that when [j] occurs in similar sequences

it is part of a complex mono-moraic nucleus with the following V. For example, the only vowel

which may follow [j] is [u] (as in cute). In addition [j] may also be preceded by a nasal (e.g.

music). The situation is complicated by the fact that in some cases [j] may be said to form part of

the onset since it is subject to some of the same restrictions as [w]. For example, neither [w] nor

22 These authors use the symbol [y] to represent the palatal glide in these sequences. In order to avoid confusion with the symbol

for the high front rounded vowel [y], here we use [j].

34

[j] may appear after a consonant + liquid cluster (Davis & Hammond, 1995). However, the

authors turn to an analysis of stress patterns to ultimately conclude that [j] is not part of the onset

since it seems to add no weight to the syllable. That is, most nouns made up of three or more

syllables in which [ju] appears in an open penultimate syllables, do not have stress on this

syllable but rather on the antepenultimate, as in áccuracy (Davis & Hammond, 1995, p. 164-

165). The few exceptions to this rule (e.g. Bermúda) would be lexically marked. This

characterization of [j] as more vocalic and [w] as more consonantal is also proposed by

Buchwald (2006, within an OT framework) who uses similar phonotactic evidence as well as the

behaviour of an aphasic patient to show that [ju] is a diphthong. These analyses are supported by

articulatory data from Gick (2003-discussed in the experimental section below) and echo the

language-specific model for glides proposed by Nevins & Chitoran (2008). Once again then we

are presented with an asymmetry between palatal and velar (dorsal) glides which is apparently

resolved differently in different languages. Recall that for Spanish and Romanian (and Italian, at

least for the mobile diphthongs) it is [j] which appears to be more consonantal while [w] is more

vocalic. For English, phonological patterning would indicate the opposite characterization for

these glides.

2.3.2 Dutch

Dutch phonologists have assumed that two categories of diphthongs exist in this language, a

distinction based on traditional impressionistic transcriptions. The first category is made up of

the genuine diphthongs (/ɛi, ʌy, ɑu/) which traditionally have been given a monophonemic

representation. The second category consists of the pseudo diphthongs (/aj, oj, uj, iw, ew, yw/)

which are given a biphonemic representation (Collier & t’Hart, 1983; Collier et al., 1982). The

presence in the language of long vowels which may be diphthongized creates more confusion

about this distinction. In terms of distribution, genuine diphthongs appear to be more closely

related to long vowels since, like these, they may be followed by a consonant in

monomorphemic words while pseudo diphthongs may not (Collier & t’Hart, 1983, p. 43).

Experimental data abounds for this language and has been focused on whether acoustic,

articulatory and perceptual data support this traditional distinction.

In addition to these two types of falling diphthongs, Dutch also has Glide-Vowel sequences

involving a palatal glide [j] (as in roeien [rú.jə] ‘to row’and fjord [fjórt] ‘fjord’) and a labio-velar

35

glide [ʋ] (as in houweel [hau.ʋíl], ‘pickaxe’ and kwaad [kʋát]), ‘angry’ (Van der Torre, 2003, p.

181-182). The latter is realized as a more vocalic [w] in weak positions (i.e. in unstressed

syllables, in syllable codas, and in word-final position), as in duwen [dý.wə] ‘to push’ (Van der

Torre, 2003, p. 181). These two glides have an asymmetrical distribution as only [ʋ] can appear

as the first element of a complex onset, giving rise to the observation that in this language [ʋ] is

more consonantal and patterns with the liquid class of sonorants while [j] is more vocalic (Van

der Torre, 2003, p. 184). This patterning is similar to that of English [j] and [w] (discussed in the

previous section) and contrasts with the patterning observed for Romance languages.

Finally, Dutch appears to exhibit anti-hiatic tendencies in its treatment of VV sequences.

Specifically, these sequences are broken up through the insertion of a glide which takes on the

characteristics of the preceding vowel, as in diet [dí.jet] ‘diet’, boa [bó.wa], and duo [dý.ɥo]

(Van der Torre, 2003, p. 189-190). This process may be handled through a glide-insertion rule

(Van der Torre, 2003). Two facts, however, call into question the necessity of a phonological

explanation. First of all, the glide [ɥ] does not otherwise occur in Dutch. In addition, no glide

insertion takes place following a low vowel or schwa, as in chaos [xáɔs] ‘chaos’ and Israël

[ɪsraɛl] ‘Israel’ (Van der Torre, 2003, p. 191). Thus, it has been suggested that gliding may

merely reflect a low-level phonetic phenomenon of coarticulation: a consequence of moving

from a high vowel to a non-high vowel in the articulatory space (Van Heuven & Hoos, 1991).

2.3.3 German

German, like English and Dutch, has falling diphthongs: [a ], [a ], and [ ] (Wiese, 1996, p.159).

Glide-vowel sequences of the form of [jV], however, also occur in this language. In these cases,

[j] is thought to represent a variant of unstressed /i/ which appears in prevocalic, non-initial

positions (Wiese, 1996, p. 234). As in Spanish, whether /i/ is realized as /j/ in these contexts is

lexically determined and subject to dialectal and interspeaker variation. Thus, while most

speakers would agree on the pronunciation of the word Union [unjó:n] ‘union’, they might

diverge in their pronunciation of Piano [pjá:no] ~ [piá:no] ‘piano’ and Tiara [tjá:ʀa] ~ [tiá:ʀa]

‘tiara’(Hall, 2008). Proximity to word stress and speech rate/style appear to be conditioning

factors in this variation (Hall, 2008). Thus, [jV] is more likely in a pre-stress position while both

[iV] and [jV] realizations are possible in a post-stress position. Also, [jV] is more common at

faster speech rates. While an overall tendency towards gliding is observed in this language,

36

gliding appears to be blocked in certain cases. First, similar to what we observed for French

above, gliding does not readily occur following complex onsets composed of Obstruent +

Liquid/Nasal (e.g. Bibliothek [bi.bli.o.té:k] ‘library’ or Bosnien [bɔs.ni.ən] ‘Bosnian’). Gliding is

also blocked following two nasals, as in and amniotisch ɪʃ] ‘amniotic’ (Hall, 2007,

p.11-13). Finally, gliding is uncommon in recently coined words with the non-native suffix -esk

‘esque’, as in hippi-esk [hɪpiɛsk] ‘hippiesque’ (Hall, 2008, p. 317). Other non-native suffixes

which appear in more established words, however, allow gliding. These include the suffix –at, as

in Stipendi-at [ʃtipɛn.djá:t] ‘scholarship holder’ and the suffix –ent, as in effizi-ent [ɛfitsjɛnt]

‘efficient’ (Hall, 2008, p. 313). The above suggests a process of lexical diffusion for German

words with non-native suffixes, similar to the patterns for liaison and elision described for

French.

2.4 Summary

The theoretical literature on vocalic sequences, both in Romance and non-Romance languages,

highlights the following issues: (i) palatal glides behave differently from their velar counterparts;

(ii) rising diphthongs may behave differently from falling diphthongs; and, most importantly for

the present dissertation, (iii) where they occur, [iV]~[jV] contrasts are variable and unstable. It

also seems that more recent theoretical articles attempt to use experimental data in formulating

new ways of looking at these sequences and their components. For example, Nevins and

Chitoran (2008) expand on data from Gick (2003) in formulating their theory of glides,

ultimately providing and explanation for the language-specific behaviour of these segments. This

appears to be the direction of recent studies: that the definition and the behaviour of vocalic

sequences vary from language to language and perhaps even from speaker to speaker. While at

first this conclusion may seem the least satisfactory, it may ultimately be the most realistic. Thus,

in the end, the best phonological answer to the question of whether glides are phonemic may be

‘it depends’. A similar answer must be given to the questions of whether diphthongs are best

thought of as monophonemic or biphonemic and whether rising diphthongs are truly diphthongs.

Again, it depends on the language and the definition of diphthong.

The experimental studies concerning vocalic sequences are examined next. However, we should

be cautiously optimistic about finding any definitive answers in experimentation. As pointed out

by Levi (2008) in her examination of phonemic glides (i.e. those which pattern with sonorant

37

consonants) and derived glides (i.e. those which are variants of underlying vowels) in various

languages, the phonological differences apparent in these presumably separate classes of glides

may not count on a matching ‘reliable phonetic difference’ (Levi, 2008, p.1974).

3 Experimental Studies

The tradition of experimental investigation of vocalic sequences is rather long and can be traced

back to the beginning of the 20th

century. An overview of this early history on diphthong and

vowel analysis is provided by Peeters (1991). Depending on the language or group of languages

being investigated, experimental studies on vocalic sequences have sought to: (i) provide an

acoustic and/or articulatory characterization of diphthongs; (ii) examine the acoustic parameters

thought to distinguish diphthongs from hiatuses, diphthongs from monophthongs, and

diphthongs from long monophthongs and/or diphthongized vowels; and, (iii) determine which of

these acoustic or articulatory parameters are crucial for identification of different diphthongs or

for the differentiation between diphthongs and other types of vocalic sequences. This section is

organized according to the primary type of experimental technique employed in the study. It

includes literature on the acoustic and articulatory parameters which have been identified as

important for vocalic sequences. This section also reviews evidence from perceptual studies

which attempt to outline which of these acoustic and articulatory parameters listeners actually

use to identify vocalic sequences and to distinguish among different types of vocalic sequences.

The more abundant acoustic studies are examined first in §3.1 and §3.2 follows with a review of

articulatory studies and their contribution to an understanding of vocalic sequences. Finally, in

§3.3 the relevant perceptual studies are reviewed. A comparison of those studies which focus on

non-Romance languages to those which focus on Romance languages (Spanish in particular)

highlights some important differences in research questions and methodology.

3.1 Acoustic Studies

Acoustic analyses of vocalic sequences have been largely influenced by the work of Lehiste &

Peterson (1961). That study introduced a definition of diphthongs which has become an

established view. In fact, the parameters and vocabulary used to identify or distinguish among

and between these sequences in subsequent studies can be traced to that study. For example, the

study used the following terminology in defining diphthongs: ‘targets’ or steady states, ‘rate of

formant change’ and ‘slope of transition’. At the risk of overgeneralizing, we can think of

38

subsequent studies as testing these various parameters to either confirm or disprove the notion of

a diphthong as consisting of two steady states or ‘target positions’ linked by a glide transition.

The assumption of a tripartite composition of diphthongs (and hiatuses in languages where these

occur) has persisted either tacitly or explicitly in most research. In fact measurements are often

taken assuming this division even when evidence shows that the first and/or second steady state

may not be present, especially at faster speaking rates or more casual speech styles (Holbrook &

Fairbanks, 1962; Gay, 1968; Aguilar, 1999) or that a glide only may be used to successfully

synthesize diphthongs (Gay, 1970). The definition of what constitutes a ‘steady state’ is fairly

straightforward and generally accepted as a period of relative stability where ‘the formants are

parallel to the time axis’ (Lehiste & Peterson, 1961, p. 272). However, there is some debate

about how long this period should be in order to qualify as a steady state. Lehiste & Peterson

(1961), for example, set the minimum at 20 ms, a time interval the authors define as “arbitrarily

chosen” (p. 272). Gay (1968, p. 1571) sets the minimum at 15 m23

.

Overall, studies of Spanish and other languages have shown that diphthongs can be distinguished

from other types of vocalic elements (such as monophthongs and hiatuses) along frequency as

well as temporal parameters, although it is acknowledged that these parameters may not define

all such sequences in all languages or even all speakers all the time. Following Lehiste &

Peterson (1961) a diphthong is generally characterized as consisting of three portions: the first

vowel target (V1), the second vowel target (V2) and the transition (T) between V1 and V2. For

Spanish and other Romance languages (i.e. Italian) research on vocalic sequences almost

invariably includes a reference to syllable structure. Thus, it may not be possible to have a

completely phonetic study in these languages; ultimately phonological concepts are called upon

either to formulate a hypothesis or to explain the results.

3.1.1 Frequency Parameters

Among the parameters identified as relevant in the characterization of diphthongs are the

formant frequencies of the V1 and V2 steady states, with researchers differing on the number of

formants to include: only F1 and F2 (e.g. Borzone de Manrique 1979; Aguilar, 1999, for

23 These times appear to be grounded in human speech perception. That is, they fall within the range of threshold values (10-40

ms) for the perception of just-noticeable differences in duration between two speech sounds (Lehiste, 1976, p. 226).

39

Spanish; Lehiste, 1967, for Estonian) or F1-F3 (Lehiste & Petersen, 1961 and Gottfried et al.,

1993 for English). Some authors (i.e. Gottfried et al., 1993) have also included measures of

fundamental frequency (f0). The general finding in these cases is that the F1 and F2 values of the

steady states of diphthongs differ from the formant values of the corresponding monophthongs.

Thus, these sequences are more than concatenated simple vowels. However, this difference is

largely language-specific. In Spanish, both onset and offset frequencies are affected (e.g.

Borzone de Manrique, 1979). In other languages, on the other hand, it may be only onset or

offset or both that are affected. For example, in Lehiste (1967) frequency measurements included

a comparison of F1 and F2 values of onset and offset components of the Estonian diphthongs

[iu], [ei], [ea], [eu], [ai], [ae], [au] and [eu] to those of their corresponding stressed short vowels.

Here the author finds that the values for the first component (onset) of the long diphthongs in

question closely correspond to those for stressed short vowels. However, the offset component

formants did not closely match the formants of the corresponding short vowels. Thus offset

frequencies but not onset frequencies may distinguish long diphthongs from corresponding V+V

sequences in Estonian. Lehiste (1967) did not look at the transition separately although its

properties are also considered important.

A second important frequency measurement involves changes in F2 from beginning to end of T

(Borzone de Manrique, 1979, for Spanish; Chitoran, 2002, for Romanian). For example,

diphthongs may be distinguished from hiatuses in the following way also: diphthongs have a

more gradual transition from V1 to V2 while hiatuses have a faster transition from V1 to V2,

reflected in a steeper F2 slope (Aguilar, 1999). In addition, in hiatuses we generally find two

clear steady states (corresponding to V1 and V2). In diphthongs, on the other hand, these steady

states may be less evident or not present for either V1 or V2 (Borzone de Manrique, 1979;

Aguilar, 1999). Still, the role of the transition on its own is disputed. For example, Jha (1985)

conducted a spectrographic study of the diphthongs /əi/ and /əu/ in Maithili24

under three

different speech rates. The results suggested that in this language onset F1 and F2 remain

relatively fixed across speech rates and the concomitant changes in duration. On the other hand,

offset targets were only reached at slow rate; at other rates the V2 steady state was rarely reached

and was often not present. Finally, the glide element changed systematically and showed a very

24 Maithili is an Indo-Aryan language spoken in India and Nepal.

40

similar F2 rate of change across the three conditions (in support of Gay, 1968). This stability in

F2 rate of change was achieved through a ‘decrease in F2 transition duration always

accompanied by a decrease in F2 offset frequency for /əi/ and an increase in offset frequency for

/əu/’ (Jha, 1985, p. 113). So, for this language F2 rate of change and onset frequency position are

very important. For English (e.g. Lehiste & Peterson, 1961; Gay, 1968), on the other hand, it is

the onset steady state which may be most important. For Spanish, different authors report

different results. For example, Borzone de Manrique (1979) suggests that, at least for Argentine

Spanish, it may be one or the other steady state depending on where the open vowel occurs on

relation to the glide (i.e. whether it’s a rising or falling diphthong). She also notes that F2 rate of

change in Spanish diphthongs appears to remain invariant across different speaking rates. On the

other hand, Toledo & Antoñanzas-Barroso (1987), also for Argentine Spanish, found significant

differences in F2 rate of change as a result of increased speech rate. Kinoshita & Osanai (2006)

in their study of Australian English /ai/ had also anticipated that the slope of F2 in the transition

would remain fairly constant regardless of speech style and would thus be a better parameter for

speaker identification that the T1 (steady state for V1) and T2 (steady state for V2) second

formant frequencies (especially since they had considerable difficulties identifying these steady

states). However, they found that (i) the angle of the slope was indeed affected by speech style

and thus was not invariant (contra Gay, 1968), and (ii) that analysis of likelihood ratios showed

that this parameter was as good, but not better than the traditional parameters in discriminating

between different speakers (in this case F2 of T1 and T2 of /ai/). However, they did find that T1

and F2 slope of the glide (G) together had better discriminatory power that any other

combination (i.e. G + T2 or T1+T2). According to Kinoshita & Osanai (2006), this ‘suggests the

possibility of the slope of the glide carrying information which complements the information that

the target carries’ (p. 117). Thus for this variety of English, it may be the combination of onset

frequencies + transition which aid in diphthong discrimination.

Spectral characteristics may also be used to distinguish between positional variants of /i u/ in

diphthongs, providing evidence of a glide continuum from more to less consonantal (Hualde,

2004). For example, Borzone de Manrique (1976) finds that in Argentine Spanish, /i u/ appearing

in diphthongs in absolute initial position (e.g. hiena [jé.na] ‘hyena’ and huelo [wé.lo] ‘I smell’)

display different spectral characteristics than those appearing in diphthongs which follow a

consonant (e.g. Viena [bjéna] ‘Vienna’ and duelo [dwé.lo] ‘duel’). Specifically, the former differ

41

from the latter in having a lower F1 and higher F2 and F3 as well as lower intensity in

comparison with the following [e]. These findings point to a greater degree of constriction, and

thus, a more consonantal realization for the variants in absolute initial position.

3.1.2 Temporal Parameters

Among the temporal parameters used to define diphthongs are measures of duration of each

portion of the sequence (Borzone de Manrique, 1979; Lehiste & Peterson, 1961), of the entire

sequence (Aguilar, 1997, 1999; Hualde & Prieto, 2002) or of only a specific portion of the

sequence (e.g. transition only: Borzone de Manrique, 1976; Chitoran, 2002; Lindau et al., 1990).

To allow for comparison of sequence of different durations, temporal measurements are often

normalized either by taking the proportion of the entire sequence taken up by the part of the

sequence measured (e.g. Lehiste & Peterson, 1961) or by manipulation of the waveform by

stretching and compressing to a common length (Aguilar, 1999).

Diphthongs are distinguished temporally from hiatuses in that hiatuses are longer (Aguilar, 1999;

Hualde & Prieto, 2002). Additionally, durational differences may be affected by the vowel

quality. For example, Aguilar (1999, p. 64) found that “hiatuses with [a] are longer than hiatuses

with [e] and [o], whereas for diphthongs, the behaviour is the opposite”. The observation that

durational patterns may be a function of the sequence being studied (as well as the language) is

also found in Lindau et al. (1990) in their cross-linguistic study of /ai/ and /au/ diphthongs in four

non-romance languages (English, Chinese, Hausa, Arabic). Specifically, they find that the

proportion of the diphthong allotted to transition duration appears to be language-specific and

ranges from 16-20% for Arabic and Hausa to 40-50% for Chinese; for English the transition is

the dominant feature and may take up to 73% of the diphthong, in the case of /au/ and up to 60%

of the diphthong for /ai/. Thus, not only is transition duration a language-specific trait, but even

within the same language, these durations may vary according to the diphthong (p. 14). Overall,

they conclude that “the timing of the diphthongal transition is not constant for the 'same'

diphthong in different languages… the transitional range and duration may be language-specific,

and possibly even diphthong-specific as well…diphthongal timing properties must be specified

as part of the phonetic description of diphthongs in different languages” (p. 14). This conclusion

echoes that of Peeters (1991) who argues, based on his perceptual study that what distinguishes

vowels, diphthongs and vowel sequences is not any particular structure or movement pattern

42

since all such sequences might exhibit movement. Where they differ is in the timing of their

movement patterns. Thus, while both a diphthong and a long vowel may exhibit a similar pattern

of movement phonetically, they will differ in terms of timing (e.g. the proportion allotted to

transition, for example may differ from one language to the next). According to Peeters (1991)

these differences are language-specific so that what defines the difference in one language may

not do so in another. Additional studies reported below seem to support this notion of the

importance of timing in different languages.

Van der Beer (2006) measured duration of Italian diphthongs and monophthongs and found the

following: (i) in terms of relative duration, rising diphthongs are comparable to monophthongs;

(ii) both diphthongs and monophthongs are shorter when in an unstressed position; (iii) mobile

diphthongs25

do not differ significantly in duration from other rising diphthongs (thus

phonetically they are not distinct); and, (iv) the asymmetry between diphthongs with [j] and

diphthongs with [w] is shown in terms of the proportion of the ratio of glide transition to vowel

in each type of diphthong (a ratio of 1:3 is found in [jV] diphthongs and a ratio of 1:2 in [wV]

diphthongs). Again, this shows that even within the same language, durational distinctions

depend on the sequence being studied.

Durational measurements are also used to distinguish between onglides and offglides,

traditionally referred to as semiconsonants and semivowels, respectively. Salza (1988) finds

durational differences to support a differentiation between onglides as semiconsonants and

offglides as semivowels in Italian, but only in unstressed syllables. In stressed syllables, their

durations become very similar. Aguilar (1997), on the other hand, also finds that there are

durational differences large enough to maintain the distinction for Spanish. However, these

differences are greater in a reading task than in a more casual speech task (Aguilar, 1997, p.

155).

It is also important to highlight here that the frequency and temporal differences between

diphthongs and hiatuses are not always clear at the acoustic level. For example, the range of

duration values for the two categories may show some overlap (Hualde & Prieto, 2002;

MacLeod, 2007) with additional blurring occurring as a result of faster speech rate or more

25 Refer to §2.2.1 above for a definition of mobile diphthongs.

43

casual speech style (Aguilar, 1997, 1999). In addition, F2 slope and the proportion of the

sequence taken up by the transition may also vary, both by dialect and by individual speaker

(MacLeod, 2007). Overall, it appears that speakers (regardless of dialect) show a higher degree

of variability in the realization of diphthongs compared to the realization of hiatuses (MacLeod,

2007). On the other hand, the diphthong category is identified as more stable than the hiatus

category (Chitoran & Hualde, 2007). The effect of this stability can be seen in the tendency for

hiatuses to diphthongize across Spanish dialects, although this tendency may be blocked under

certain prosodic conditions. For example, exceptional hiatuses are more likely to resist this

tendency in conditions that induce lengthening, as in word-initial position and in stressed

syllables (Chitoran & Hualde, 2007). In addition, the tendency to diphthongize may proceed at

different rates between certain varieties (Garrido, 2007; Colantoni & Limanni, 2010) and for

different speakers (Colantoni & Limanni, 2010). Finally, speakers may select different

coarticulatory strategies to achieve the diphthong-hiatus contrast. For example, Colantoni &

Limanni (2010) present evidence which suggests that speakers of contact and non-contact

varieties of Argentine Spanish use different coarticulatory strategies to achieve diphthongization

in rising sequences. Specifically, the contact variety achieves diphthongization through a shorter

and more coarticulated V1 (the high vocoid). The non-contact variety, on the other hand, does so

through a longer transition (Colantoni & Limanni, 2010, p. 30-31).

3.1.3 Summary

Overall, the acoustic studies reviewed above seem to suggest that the relevant durational and

frequency cues which characterize vocalic sequences may be language-specific and even

sequence-specific. This observation underscores the need to study different languages and

different sequences within those languages, even though many studies tend to focus on the

maximally distinct ones of the type [aj]/[ja]. In addition, individual variation on these two

measures suggests that even speakers of the same variety cannot be treated as a uniform group,

emphasizing the need to consider individual strategies in the use of these acoustic parameters

(and their underlying articulatory correlates). Finally, the acoustic studies also point out that

diphthongs cannot under most circumstances simply be thought of as concatenations of two

vowels. That is, they are different from the sum of their parts. This qualitative difference

between diphthongs and monophthongs is succinctly described in Beberfall (1962, for Spanish)

through an analogy with chemistry: “This characteristic of diphthongs is comparable to what is

44

manifested when two elements combine to form a chemical compound. For example, harmless

sodium chloride can hardly be traced back mechanically to the constituent caustic sodium and

toxic chlorine. Just as sodium chloride is a new product, so is the au diphthong in causa, aula

and in any other word where it is found” (Beberfall, 1962, p. 38).

3.2 Articulation Studies

The studies reviewed above have contributed to the acoustic characterizations of diphthongs,

vowel sequences (i.e. hiatuses or vowel clusters, depending on the language) and vowels in

general. Fewer studies have examined the articulatory properties of these elements. This

experimental gap is understandable given that techniques for acoustic analysis are more readily

available, considerably less expensive to operate, and less invasive than those typically used for

articulatory analysis (see Stone, 1997 for a review of various techniques used in articulatory

research). In addition, data for acoustic analysis may be obtained from a large number of

speakers whereas articulatory studies are often limited to as few as a single speaker (often the

author, depending on the type of instrumentation and degree of invasiveness). Moreover, it is

possible to infer articulatory characteristics from acoustic data. However, it is also acknowledged

that some articulatory-acoustic relations may not be linear (i.e. a set of specific formant values

may not correspond to a single, invariant vocal tract shape) and that using articulatory data to

complement acoustic data increases explanatory power (Recasens, 1999a). The studies reviewed

in this section serve to highlight the value of articulatory data (whether primary or synthesized)

to support or challenge acoustic and theoretical findings.

Kent & Moll (1972) undertake a cinefluorographic (X-ray) analysis to examine the effect of

phonetic context on the articulation of American English vowel + vowel (e.g. /i/ + /o/, as in

Leo’s), diphthong + vowel (e.g. /aɪ/ + /o/, as in viola) and diphthong + diphthong (/aɪ/ + /ɔɪ/, as in

hyoid) sequences. These vocalic sequences were examined in contexts were they were either

adjacent or separated by a non-lingual consonant (p. 280), both within or separated by a word

boundary. The authors looked at two tongue body points and used jaw movements as reference.

Overall, they found little effect of the phonetic context on tongue movement in the sequences

studied. However, they did find an important relationship between the magnitude and rate of

tongue movement for the vowel + vowel sequences. That is, the greater the tongue displacement,

the faster the rate of movement of the tongue. Thus, they find greater mean and peak velocities

45

for /i/ + /ɑ/ than for /i/ + /æ/ since the former requires a greater displacement of the tongue. For

the diphthongs /aɪ/ and /ɔɪ/, they find that “the initial and terminal tongue positions are not

invariant attributes of diphthong production” (Kent & Moll, 1972, p. 292). Hence, the onset and

offset frequency values are not what distinguish one diphthong from another. Rather, they

suggest that “the movement patterns in themselves are sufficient to distinguish /aɪ/ from /ɔɪ/” (p.

292). These patterns of movement for a given diphthong remain similar across different

productions and across differences in tongue displacement. The authors thus conclude that

diphthong production differs from vowel + vowel production in that diphthongs exhibit a relative

independence of magnitude of tongue displacement and tongue movement velocity. They

consider this as “suggestive of a constraint on the velocity of articulatory movement during

diphthong production” (Kent & Moll, 1972 p. 295) and as support for a theory of invariant

formant movement rate in diphthongs (e.g. Gay, 1968). However, their data does show

exceptions to this invariance. In particular, their data for /aɪ/ shows much greater tongue

displacement in the word hyoid than in the phrase I hold (Kent & Moll, 1972, Fig. 11, p. 293),

although the authors dismiss this as an atypical example. In addition, they found a large amount

of individual variation between the two participants. Specifically, these participants displayed

different tongue body-jaw patterns. The male participant tended to use only small jaw

movements while the female speaker used large jaw movements. Thus, while their vocal-tract

configurations were similar for individual segments (e.g. for /i/, p. 282) they each employed

different strategies for achieving the different configurations required for the sequences they

produced in the study. This finding leads the authors to suggest that phoneme targets are best

defined as “spatial attributes of the vocal tract rather than as invariant motor commands to the

component articulators” (Kent & Moll, 1972, p. 296).

Shaiman & Porter (1991) took strain gauge measurements of the upper lip and jaw movements of

six speakers as they produced the vowels /ɑ i/ and the diphthongs /eɪ aɪ / in the fixed segmental

context /pV#pVp/ (#=syllable boundary and V=vowel or diphthong) under two stress conditions

(stressed=stress on first syllable; unstressed=stress on second syllable). Measurements of

articulator displacement and velocity were used to calculate phase angles in order to compare the

timing relationship between the two articulators. These measurements revealed that vowels and

diphthongs differ in the relative timing of upper lip and jaw movements. Specifically, larger

phase angles were found for the diphthongs than for the vowels. That is, the onset of upper lip

46

movement occurred later in the jaw cycle for diphthongs. The authors claim that the difference

occurs as a function of jaw opening duration percentage. Specifically, maximum jaw opening is

reached earlier within the total jaw cycle for diphthongs, perhaps reflecting “the need of the

tongue + jaw synergy to accommodate movement between successive vowel targets” (p. 3006).

Thus, different phase relationships of vowels and diphthongs are achieved by changing the jaw

cycle characteristics rather than the timing of upper lip movements. Phase angle values were

similar for the two vowels and for the two diphthongs. Thus, vowel height (of /ɑ / vs /i/) does not

appear to influence the upper lip-jaw phasing relationship. Similarly, /eɪ/ and /aɪ/ could not be

distinguished by differences in phasing. The unstressed condition (where the first syllable was

unstressed) produced smaller phase angles for both and resulted in smaller differences in the

phase angles for diphthongs and vowels. Thus, while the overall differences between vowels and

diphthongs were maintained in the absence of stress, these differences were reduced so that

diphthongs and vowels “appear more alike” (p. 3006) in this condition. An interesting and

important finding of this study is that two of the participants showed very little difference in

phase angle between vowels and diphthongs. However, they did display the same pattern as all

the other speakers, leading the authors to conclude that “the value of the phase angle itself is not

critical: rather, within a given speaker, the relationship between phase angles for different tasks

is the salient variable” (Shaiman & Porter, 1991, p.3005).

Gick (2003) undertakes an EMA study with three participants to investigate syllable position

effects on phasing relationships in the American English glides /j/ and /w/. His analysis of these

glides in prevocalic and postvocalic positions shows important differences between initial and

final allophones. For both /j/ and /w/, the final allophones (VC, postvocalic position) show a

reduction in gestural magnitude, suggesting they are more vowel-like than the initial allophones

(CV, prevocalic position). Similarly, Kochetov (2006) finds syllable-position effects for Russian

/j/ using EMMA. For example, he reports a consistent reduction in the magnitude of the TB

raising gesture in coda position as compared to onset position (Kochetov, 2006, p. 576). He also

observed a reduction in the magnitude of TB fronting as well as a decreased duration of TB

raising of Russian /j/ in coda position but these effects were more variable.

Gick (2003) also observes a crucial difference between English /w/ and /j/. Namely, he finds

evidence that /w/ consists of two gestures, one vocalic (tongue body/dorsum raising), which he

terms a V-gesture, and one consonantal (lip constriction), which he calls a C-gesture. The

47

relative phasing of these two gestures differs according to syllable position. Thus, in final

position /w/ shows both a reduction in lip constriction as well as a relative lag of this C-gesture

(a lip delay) relative to the V-gesture. In initial position, the opposite effects are seen (i.e. greater

lip constriction; C-gesture occurs prior to V-gesture). This analysis of syllable position effects on

/w/ offers support for the CV vs. VC phasing relations proposed by Browman & Goldstein

(2000). On the other hand, Gick (2003) finds that /j/ appears to be composed of a single V-

gesture (involving tongue body raising and fronting). This gestural distinction between /j/ and

/w/ can account for differences in the phonological behaviour of these two glides in English

(Davis & Hammond, 1995). Gick (2003) also suggests that results for these glides may be

different in other languages. That is, V-gestures and C-gestures are language-specific and

phonologically specified. Thus, for Italian (Marotta, 1987), and possibly Spanish (Nevins &

Chitoran, 2008), [j] may be more consonantal than [w], while for Romanian, both [w] and [j]

may be considered more consonantal than vocalic (Marin, 2007). In addition, a recent EMA

study by Zmarich et al. (2012) suggests that for Italian, prevocalic [w] differs from postvocalic

[w] only in degree of constriction. That is, the onglide shows a greater lip constriction (thus, is

more consonantal) than the offglide. No significant differences in C-gesture (i.e. lip) lag were

found. This result suggests that, at least for this language, onglides and offglides differ featurally

rather than structurally. However, these results are only for [w] and only from a single speaker.

Based on those results, it is not possible to say whether Italian [j] behaves in the same manner.

We also do not know whether all Italian speakers use only degree of constriction to distinguish

between onglides and offglides. It may be that both degree of constriction and phasing are

available as articulatory strategies but individual speakers are able to exploit them to different

degrees.

Collier et al. (1982) collected EMG as well as acoustic data from a single Dutch speaker (the

principal author) during the production of diphthongs and vowels. This data was meant to

complement existing acoustic and perceptual data pointing to two categories of diphthongs in

Dutch: ‘genuine diphthongs’ (traditionally described as having a monophonemic representation)

and ‘pseudo diphthongs’ (described as biphonemic sequences of vowel + glide). The authors

tested the hypothesis that genuine diphthongs could be characterized as comprising a single

gesture while the pseudo diphthongs comprise “two discrete, concatenated gestures” (Collier et

al., 1982, p. 310). To test the hypothesis, the authors collected data on the activity of the

48

following muscles (p. 308-309): the genioglossus (responsible for tongue advancement); the

styloglossus (responsible for tongue body retraction); and, the mylohyoid (acts with the other

two muscles to elevate the tongue, providing most of its vertical thrust). The results support the

characterization of genuine diphthongs as single events since gesturally they appear dominated

by the activity of a single muscle. In the case of /ɛi/ the genioglossus is dominant, in the case of

/ɑu/ the styloglossus dominates, and in /ʌy/ it is the mylohyoid muscle. The ‘pseudo diphthongs’,

on the other hand, show two distinct mylohyoid peaks, with the genioglossus and styloglossus

aligned with one or the other peak. The results thus support the phonological characterization of

‘pseudo diphthongs’ as biphonemic. However, because the data came from a single speaker it is

not possible to say whether different speakers would use the same articulatory strategy to

differentiate between these two classes of diphthongs.

The above studies used primary articulatory data. The following study (Marin, 2007) used

synthesized articulatory data to test hypotheses about the differences between Romanian

diphthongs, hiatuses, vowels and glide-vowel sequences. The main proposal put forth by Marin

(2007) is that in Romanian the phonological diphthongs /ea/ and /eo/ represent two vowels which

are synchronously coordinated. When the two gestures have different weight (as when /a/ is

stressed), the percept is of a diphthong. When the two gestures have equal weight (in the absence

of stress), gestural blending occurs and /e/ is perceived. Marin (2007) uses the Task Dynamic

Application (TADA) computational system to model the /e/-/ea/ alternation. This was done by

starting with a base stimulus consisting of /e.a/ in hiatus and manipulating the amount of overlap

between the two. A perceptual study which followed revealed that listeners perceived the

sequences with least overlap (sequential coordination of the vowel gestures) as hiatus, those with

more overlap (synchronous coordination) as diphthongs and those with the most overlap

(blending of two equally weighted gestures) as /e/. The author argues that durational changes

alone could not be responsible for these results since even the shortest stimulus presented to the

listeners fell within the range of natural diphthong durations (as produced in the acoustic study

which preceded the articulatory simulation). The author then proceeded to alter the articulatory

strength of each of the vowels in an effort to simulate stress effects. The results show that when

[a] is weighted more heavily, listeners perceive a diphthong. However, when the two vowels are

weighted equally, the listeners perceive the single vowel [e] (Marin, 2007, p.121). The author

49

interprets these results as favouring her hypothesis. However, she acknowledges that parameters

other than articulatory weight may be needed in order to model the effects of stress.

For Spanish, there are recent attempts, motivated by Browman & Goldstein (2000) as well as by

some of the above studies, to relate articulatory analysis to the differences between diphthongs

and exceptional hiatuses. In particular, it has been suggested that diphthongs and hiatuses display

different gestural coordination patterns (Chitoran & Hualde, 2007). These authors extend an

analysis of syllable position effects on the gestural coordination of CV sequences (Browman &

Goldstein, 2000) to vowel-vowel (VV) sequences. They suggest that diphthongs, like CV

sequences, are characterized by a synchronous coordination mode while hiatuses are

characterized by a sequential coordination mode, as in VC sequences (Chitoran & Hualde, 2007,

p. 61). Since a synchronous relation is considered more stable and a sequential one less stable

(Browman & Goldstein, 2000), this characterization predicts more variation in the production of

hiatuses. However, because these analyses do not come from articulatory data, it remains

uncertain whether Spanish vocalic sequences can be characterized with the same gestural

coordination patterns as sequences of consonants and vowels.

3.2.1 Summary

One of the main points that can be taken away from these studies is that the relevant articulatory

cues which characterize vocalic sequences may (just as we saw for the acoustic cues) differ by

language and even by type of sequence. The studies also suggest that individual speakers may be

able to exploit different articulatory strategies to make the relevant distinction between types of

vocalic sequences. Finally, all these studies serve as an important complement to existing

acoustic and theoretical literature on vocalic sequences. That is, they provide details of the

articulatory parameters underlying the acoustic differences (e.g. Collier et al., 1982). In addition,

they can be used to test featural and syllabic theories of glide production (e.g. Gick, 2003;

Zmarich et al., 2012).

3.3 Perception Studies

Carefully designed perception studies can be important for confirming or challenging hypotheses

based on acoustic and articulatory data and for testing the relationship between production and

perception. In addition, they may play a significant role in testing phonological analyses of glides

50

and vowels. Consequently, perception studies play a crucial role in understanding the differences

between diphthongs and hiatuses. Importantly, they have the potential to help determine the

status of exceptional hiatuses.

While perception studies for vowels, diphthongs and vocalic sequences in English and other

Germanic languages in general are readily available (e.g. Gay, 1970; Bond, 1978; Bladon, 1985;

Peeters & Barry, 1989; Peeters, 1991; Schouten & Peeters, 2000; Morrison & Nearey, 2007),

fewer studies exist for Spanish (or other Romance languages). Perception data for the former set

of languages has generally employed synthesized stimuli and has focused on the following

questions: (i) what parts of a diphthong are necessary for its perception? (ii) how are diphthongs

differentiated from monophthongs and/or vowel sequences? and (iii) how do listeners

differentiate between different diphthongs? Again, Lehiste & Peterson (1961) can be identified

as an overarching influence in these studies. Specifically, it appears that Lehiste & Peterson

(1961) provided the perceptually relevant parameters which this line of research seeks to identify

as most significant in the identification of these sequences.

On the other hand, studies on Spanish and other Romance languages (e.g. Van der Beer, 2006,

Gili Fivela & Bertinetto, 1998, for Italian; Chitoran, 2002; Marin, 2007 for Romanian) have

either used a different methodology and/or have focused on answering the following questions:

(i) can listeners distinguish between diphthongs and hiatuses/bivocalic

sequences/monophthongs?; (ii) do their perception results match their production results?

Frequently, the first question has been approached through syllabification intuition tasks with

these results then being used to answer the second question. Exceptions to the

syllabification/intuition approach include Van der Beer (2006), Chitoran (2002), and Marin

(2007). Because of these differences in questions and methodologies, studies on Spanish and

other Romance languages are reviewed separately from those studies on non-Romance

languages.

3.3.1 Spanish

For Spanish, researchers have relied on the syllabification intuitions of native speakers as a cue

to whether these speakers make the contrast between hiatus and diphthongs. Experiments have

generally focused on the difference between exceptional hiatuses and diphthongs in similar

consonantal environments and have concentrated on sequences of a high front vowel [i] /palatal

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glide [j] in combination with [a]. For example, Hualde & Prieto (2002) administered such a task

to their participants (6 speakers of the Madrid variety of Peninsular Spanish) following a

production experiment in which they produced the target words, all of which contained

sequences of unstressed [i j] and the stressed vowel [a]. Syllabification categories were decided

by the authors, according to their intuitions as native speakers of this variety of Spanish. Thus,

sequences were classified as either diphthongs or (exceptional) hiatuses, as in the examples

below:

(17) (a) hiatus: el piano [elpi.áno] ‘ the piano’

(b) diphthong: Ulpiano [ulpjáno] ‘Ulpiano’ (a personal name)

For the task, the participants were presented with a written list of the target words and were

asked to decide how many syllables each word contained (by dividing the word into syllables or

tapping or otherwise counting out the syllables) and write down this number beside the word.

They report that only one participant out of six (speaker JT) deviated considerably from his

production performance. JT’s performance was attributed to his lack of awareness of the

‘phonological’ contrast in words which he produced as hiatus but syllabified as diphthong. This

was particularly evident in the word barriada ‘neighbourhood’, a word hypothesized by the

authors to be in the diphthong class. In fact, this particular word created difficulties for other

speakers as well, leading the authors to observe that if this word were excluded from the data, the

participants’ production and syllabification would coincide more closely. The authors conclude

that for JT this particular word belongs to the hiatus category while for some of the other

speakers it “may fluctuate between the two classes” (Hualde & Prieto, 2002, p. 232).

A similar approach is taken by Face & Alvord (2004). Their study was an attempt to replicate the

findings of Hualde & Prieto (2002) for a different variety of Peninsular Spanish (a contact

variety, Spanish-Catalan). In their study, the 5 participants were all speakers of the Barcelona

variety of Peninsular Spanish; bilingual Spanish-Catalan speakers who spoke primarily Spanish.

A production task determined that the speakers indeed produce a diphthong-hiatus contrast in

this variety of Spanish, as shown by durational differences between the two types of sequences:

for each individual speaker, the sequences which were hypothesized to be hiatuses were

significantly longer than those hypothesized to be diphthongs. These results, as well as the

findings of intra and inter-speaker variability in duration, echo those found by Hualde & Prieto

(2002). In other words, there are two kinds of durational overlap: individual speakers may show

52

overlap between diphthongs and hiatuses in terms of duration (when raw numbers rather than

means are compared) and their mean values may differ from those of other speakers. For

example, one speaker’s mean diphthong duration may approach another speaker’s mean hiatus

duration. A different set of participants (10 in total) took part in a second experiment involving

three perception tasks. The goals of these tasks were (i) to replicate the study by Hualde & Prieto

(2002) and (ii) to test perception aurally as well as in terms of syllabification based on written

words. In the first task, listeners heard words from the production experiment presented to them

via headphones. The listeners heard a total of 16 stimuli, 8 of which were altered so that a word

which normally contained a hiatus had that hiatus portion replaced with a diphthong and vice

versa. Listeners heard each word twice, once in its original state and once in its altered state. This

was done to avoid as well as to test for lexical bias, the rationale being that if lexical bias was at

work, then the altered word would be heard in its original form. Participants were asked to report

the number of syllables produced by a speaker for a particular sequence by writing the number

down on a paper. In a second task, participants were asked to syllabify the same sequences as

they themselves would produce it. The purpose of this second task was to compare these results

with those of the production task to see if the results coincide. Finally, in a third task, participants

were asked to identify vowel sequences in isolation as either diphthongs or hiatuses. These

sequences were taken from the words used in the first perceptual task. Therefore, it is possible

some of the formant transitions related to the consonantal context may have been left in, giving

listeners a cue as to the lexical item. In general, however, participants did well in these tasks,

correctly identifying diphthongs and hiatuses, both in isolation and in their natural word

environments (whether modified, switched or not) at well above chance levels. One important

observation was that listeners more often erred on the side of diphthongs, suggesting that when

they are unsure as to one or the other, they will choose a diphthong syllabification over a hiatus

syllabification. The authors attribute this to a frequency effect in the language. That is, in

Spanish most cases of a high vowel-vowel sequence are produced as diphthongs rather than

hiatuses (hence the term exceptional hiatus). An alternative explanation in terms of marked

sequences is also offered. This second explanation assumes that [i.a] is lexically marked while

[ja] is unmarked and thus the second is preferred (if we invoke a theory of markedness where

marked items are dispreferred). This second explanation also requires the assumption that

syllabification is stored in the lexicon and included in underlying representation. Interestingly,

the same word (barriada, ‘neighbourhood’) was a point of disagreement here as well (see

53

Hualde & Prieto, 2002, above). It is the only word where most of the speakers (3 out of 5)

disagreed with the hypothesized syllabification (they syllabified it as hiatus rather than the

hypothesized diphthong), leading the authors to suggest (in a footnote) that a preceding [r] may

promote hiatus.

One possible limitation of the above studies is that they may not reflect perception of the

diphthong-(exceptional) hiatus contrast as much as they reflect how well the person learned to

syllabify certain words in school, in particular where words are presented in their written form.

Another possible limitation is the focus on sequences with the vowel [a] since the articulatory

distance between this vowel and the high vowel/palatal glide may be contributing to the longer

duration and thus to the assumed hiatus percept in these sequences. Thus, the existence of

exceptional hiatuses may be overstated. The hiatus pronunciation of these sequences may simply

reflect articulatory constraints. In fact, it would appear that for many speakers of Peninsular

Spanish, the variety which is said to consistently produce exceptional hiatuses, such sequences

are assigned a diphthong syllabification.

Cabré & Prieto (2006) found this tendency towards a diphthong syllabification of ‘exceptional

hiatuses’ in sequences consisting of high vowel/palatal glide + V. Their study employed a similar

methodology in which a pen-and-paper questionnaire was administered to a total of 15

Peninsular Spanish speakers from different areas of Spain. A corpus of 246 words was included

in the questionnaire. These words were designed to test the effects of various factors on the

participants’ syllabification decisions, which they were to indicate by separating the words into

syllables. These factors included: (1) position in word (initial position thought to favour hiatus);

(2) morphological effects (presence of morphological boundaries thought to favour hiatus); (3)

paradigm effects (a hiatus in a morphologically related word will block diphthongization). The

results show that not all speakers show the initiality effect (1), leading the authors to distinguish

between ‘conservative’ (who tend towards hiatus preservation and judge less that 50% of the

sequences as diphthongs) and ‘innovative’ (who tend to judge the majority of sequences as

diphthongs) speakers, although they comment that ‘there is no clear separation’ between these

two groups, rather, a ‘gradual situation’ (p. 207). In addition, they find that nouns and verbs

behave differently in terms of morphological and paradigm effects. In nouns, for example, uV

sequences (e.g. virt[u.ó]so ‘virtuous’; act[u.á]l ‘present’) are more resistant to diphthongization

than iV sequences (e.g. od[jó]so ‘hateful’; cord[já]l ‘cordial’). In verbs, a form with a stressed

54

high vowel in combination with a morpheme boundary in some form of the paradigm appears to

be required for hiatus preservation (e.g. conf[i.á]r ‘to trust’ with exceptional hiatus, conf[í.o] ‘I

trust’ vs. camb[já]r ‘to change’, with diphthong, cámb[jo] ‘I change’, p. 207). As with effect (1),

many speakers in the sample do not show effects (1) and (2) and have generalized the diphthong

production to these environments. Overall, the study confirms that Spanish in general presents a

tendency to diphthongize. The authors account for this tendency with a correspondence-based

OT analysis. In addition, they propose a universal constraint of PROSODIC PROMINENCE to

account for the tendency for glide formation to be blocked in the phonetically strong initial

position. An important limitation of this study is the fact that the participants gave written rather

than spoken responses. On the other hand, an important contribution of this study is its

recognition of the fact that diphthongs may be more widespread in this variety than previously

recognized and that there are great inter-speaker differences in the distribution of ‘exceptional

hiatuses’. The authors account for this variation “by assuming that each speaker is able to set up

a set of idiosyncratic correspondence relations between different words which are active in the

evaluation process” (p. 233). This statement echoes comments by Docherty (2003) who suggests

in his review of Goldinger & Azuma (2003), Remez (2003) and Local (2003) that an important

implication of assuming a “multiple-trace account of perception and representation whereby

multi-modal experience is encoded in memory, is that, to the extent that speakers of the same

language (even from the same community) have different experiences, they may have built up

slightly different bases on which to interpret the sound patterning to which they are exposed”

(Docherty, 2003, p. 344). He suggests that studies should pay closer attention to individual

differences in production and perception and rethink any assumptions about “linguistic

homogeneity” when selecting participants for such studies.

The results from Whitley (1985) also serve to underscore the importance of controlling for

variation in participants. This author employs a questionnaire methodology in an attempt to

answer the question of whether speakers maintain a phonemic contrast between [i] and [j]. In the

questionnaire, 25 native Spanish speakers from 12 different countries were presented a list of

<yV> or <(h)iV> initial words. The participants’ task was to place the appropriate form of the

coordinating conjunction y [i] ‘and’ before the words. This conjunction undergoes a

morphophonemic change when it occurs before /i/-initial words: it becomes e /e/. Thus, we have

madre y abuela ‘mother and grandmother’ but madre e hija ‘mother and daughter. Whitley

55

(1985) calls this change ‘Conjunction Lowering’ and proposes that participants will apply this

rule before words they perceive as iV-initial (i.e. with initial hiatus) but not before words they

consider to be jV-initial (i.e. with initial diphthong, or non iV-initial). His results show a great

influence of orthography. Speakers consistently (around 75% of the time) applied conjunction

lowering before most i-initial words and failed to apply it 100% of the time in y-initial words. On

the other hand, hi-initial words26

exhibited more variation. On the whole, Conjunction Lowering

was more common with “technical or foreign-looking vocabulary” and less common with

“ordinary words” (Whitley, 1985, p. 373). Thus, frequently used, easily recognized words were

more likely to be given a diphthong interpretation while less frequent ones were more likely to

retain a hiatus interpretation. However, what counted as ‘ordinary’ and ‘frequent’ differed from

speaker to speaker. In this case, the influence of dialect was unclear, with different speakers of

the same dialect showing more or less of a hiatic tendency. What appeared to make a difference

was level of education. That is, speakers with the highest levels of education were more likely to

have assimilated some of the less common words into the diphthong category, presumably

because they were more familiar with them (Whitley, 1985, p. 376). The author concludes that a

hiatus pronunciation of /iV/ sequences is un-Spanish and is limited to a small set of “relatively

unusual” (Whitley, 1985, p. 377) words not yet fully assimilated into the language. This set of

words is smaller for highly educated speakers who may regularly use them (or at least be more

aware of them).

3.3.2 Italian

A syllable-intuition methodology was employed by Gili Favela & Bertinetto (1998) in their

study on a hiatus vs. a diphthong pronunciation of vowels which come into contact between

word prefixes and roots. The study tested possible influences on this judgment, including (i)

prefix length (a longer prefix is predicted to result in a diphthong judgment); (ii) segmental

factors, i.e. the quality of the vowels in contact (high vowels /i u/ more likely to diphthongize

due to inherently shorter duration); (iii) the distance of the prefix-final vowel from the stress in

the root (diphthongization becomes more likely the further away the stressed vowel is from root-

initial position); (iv) word frequency effects (more common words predicted to have a

26 Some i-initial words also fell into this category. however, all these were words with more than two syllables and in all cases

the word stress did not fall on the initial iV sequence (e.g. iatrogénicas ‘iatrogenic-fem. plural’).

56

diphthong); (v) semantic factors whereby a prefix creates a contrastive meaning compared to the

same root without the prefix (this would create a hiatus environment); (vi) regional origin of

participant (assumption is that judgments may vary according to regional preferences). In this

study a corpus of words was presented in written list form to 14 participants from different

regional areas of Italy. The results support most of the expected influences on judgment but had

some surprising revelations. First, the participants were found to be very liberal in assigning

diphthong pronunciations (they did this to around 50% of the stimuli), in line with what was

found for Spanish (Face & Alvord, 2004; Cabré & Prieto, 2006). Second, the regional origin of

the participant did not turn out to be significant, although the authors suspect that people from

different regions may weight the various influencing factors differently. Finally, an important

observation pertains to the auditory classification of these sequences on the part of the authors

(done as participants were asked to read the stimuli aloud as part of their interview process).

They find that with repeated exposure to the same sequences, the authors tend to judge more of

them as diphthongs. This observation is particularly relevant for studies which assign participant

productions of such sequences to one category or another based on the auditory discrimination of

the researchers.

Van der Beer (2006) uses a different methodology to explore the asymmetry in perception

between front and back mobile diphthongs in Italian. To set up his perception study, he uses a

speech shadowing task. In this task, 10 native Italian speakers listened to a series of 16

sentences, as recorded by another native Italian speaker, containing the words in which the target

diphthong (either [jɛ] or [wɔ]) or the corresponding simple vowel ([e] or [o]) was removed and

replaced by noise. Because of lexical conditioning effects, nonsense words were also included in

the sample. The job of the participants here was to repeat each utterance as soon as they heard it,

thus presumably filling in the missing portions with either a diphthong or monophthong. In the

second production task, the same 10 speakers were asked to read a list of target words (including

nonsense words) and apply a specific morphological operation (i.e. diminutivation, inflection, or

derivation) to these. From the above two tasks, the researcher collected a total of 217 stimulus

items which were then used for a third task, the perception task. During this final phase, the

tokens were presented to five listeners who then judged whether the token included a diphthong

or a monophthong. These five judges included two Dutch phoneticians and three native speakers

of Italian with no background in phonetics. The results showed that, while the Italian listeners

57

tended to hear more diphthongs than the Dutch, overall both groups of listeners perceived

diphthongization more often with unstressed front vowels than with unstressed back vowels (at

rates of 85% vs. 64%, respectively), suggesting that back diphthongs are indeed more resistant to

levelling effects. That is, front diphthongs are more likely to spread to unstressed positions than

back diphthongs. Van der Beer proposes a perceptual explanation for this phenomenon,

suggesting that the back diphthongs are more likely to be confused with their corresponding

monophthongs, especially in the absence of stress, because they present a “more parallel and

slightly less extended movement of F1 and F2” (Van der Beer, 2006, p. 65) than the front

diphthongs. The first two formants of these back diphthongs, in fact may be so close together (a

difference of approximately 300 Hz) that they “may combine into a single perceived peak” (Van

der Beer, 2006, p. 66). Besides identifying a perceptual asymmetry between front and back

diphthongs, this study also taps into the cross-linguistic differences in judgment of the

diphthong/monophthong distinction. That is, the fact that Dutch listeners perceived more

monophthongs may reflect findings that Dutch speakers prefer their diphthongs with glide

durations of around 120-140 ms (Peeters & Barry, 1989; Peeters, 1991, p. 304) while the mean

glide duration produced by the Italian speakers here was around 52 ms for [w] and

approximately 35 ms for [j] (Van der Beer, 2006, p. 44). The Dutch speakers may have had

difficulty perceiving these short transitions as glides and thus could not make the same

distinction between diphthongs and monophthongs as the native Italian speakers. On the other

hand, if glide duration alone was the selection criterion, we would predict that the Dutch would

hear more monophthongs with [j] since this glide was shorter than [w].

3.3.3 Romanian

Perception experiments for Romanian employ identification and discrimination tasks rather than

syllabification/intuition tasks. In addition, the stimuli used in these experiments have been

excised from production data, thus controlling for lexical bias.

Chitoran (2002) followed up a production experiment where she identified the acoustic (temporal

and spectral) differences between glide-vowel sequences <ia> [ja] and <ua> [wa] and their

corresponding diphthongs <ea> [ea] and <oa> [oa]. Based on the acoustic results, the author

predicted that listeners would be able to correctly distinguish between [ja] and [ea] since these

differ on the acoustic parameters measured. However, she predicted that the participants would

58

have difficulty distinguishing between [wa] and [oa] since no acoustic differences were found

between them. Fourteen native speakers of Romanian heard the sequences and were asked to

identify them by choosing the orthography that corresponded to what they heard <ia> or <ea>,

and <ua> or <oa>. The results closely matched the predictions. The participants correctly

identified [ja] vs. [ea] at a statistically significant rate. On the other hand, identification of [oa]

vs. [wa] was roughly at chance level. The implications of the study are as follows: (i) the

acoustic differences translate into perceptual differences, and (ii) phonological differences (i.e.

between [oa] and [wa]) are not always manifested phonetically. The author suggests that the

explanation for (ii) requires references to both language-specific and language-universal

properties of such sequences (Chitoran, 2002, p. 220-221). First, the sequence [wa] in Romanian

is relatively infrequent, appearing in a few lexical items which are primarily loanwords. In

addition, there is relatively little acoustic difference between [w] and [o], thus this contrast is

inherently difficult to perceive. This observation is in line with findings reported in Van der Beer

(2006), reviewed above.

Marin (2007) uses both identification and discrimination tasks to test her articulatory hypothesis

regarding Romanian diphthongs as synchronously coordinated. Her perceptual experiments

predict that two vowels ([e#a] and [o#a]) which come together across a word boundary will be

perceived as follows (i) as a diphthong when stress gives one of the vowels more prominence, or

(ii) as a single blended vowel when both vowels have equal prominence in the absence of stress.

Consonantal environment was carefully controlled for and all VV sequences were cropped from

production data in a t_p context. For the identification task, the 10 participants heard the

sequences produced by 5 different speakers at 5 different speech rates (as controlled in the

production task through a visible metronome) and had to decide whether they perceived a

diphthong, a single vowel ([e] or [o]) or something else. The results of this first experiment show

that at the fastest rate (5) more diphthongs were heard in the stressed condition and more single

vowels in the unstressed condition. The author interprets these results as supporting her

hypothesis that increases in speech rate result in a “sporadic shift to synchronous coordination

between two vowels” (Marin, 2007, p. 73). This shift in turn leads to the percept of a single

vowel in the absence of stress and of a diphthong in the presence of stress. However, there are

also some asymmetries evident between [e#á] and [o#á] clusters (Marin, 2007, p. 72). Namely,

even in the presence of stress, 23% of [o#á] clusters are still heard as the single vowel [o],

59

whereas only 1% of [e#á] clusters are heard as [e]. The author does not mention this asymmetry

but suggests that fast speech rate causes a loss of boundary and/or stress information, resulting in

a vowel percept. A discrimination task of the AXB type was subsequently used to test perception

at the two fastest speech rates. In the task, the experimental stimuli (X) were presented together

with a diphthong and a single vowel (A and B). The listeners were asked to decide whether X

sounded more like A or more like B. The results from this task show a similar asymmetry as the

one identified in the previous task. That is, more of the unstressed [o#a] sequences (60%) were

perceived as a single vowel than the unstressed [e#a] sequences (19%). This asymmetry suggests

that the synchronous coordination hypothesis proposed by this author is not a case of all or

nothing (i.e. synchronous vs. asynchronous). Rather, there may be degrees of coordination in

vowel-vowel sequences which are more or less synchronous and which are affected by speech

rate and by vowel quality.

3.3.4 Non-Romance Languages

Most perceptual studies conducted on non-Romance (especially Germanic) vowels and

diphthongs have attempted to provide evidence for the relevant parameters which permit

identification of vowels and diphthongs. These studies can be thought of as testing and

comparing one of three possible hypotheses, summarized as follows in Gottfried et al. (1993):

(18) vowel and diphthong hypotheses

(a) onset + offset hypothesis: the relevant cues are the formant values (i.e. F1 and F2)

at beginning and end of the vowel or diphthong

(b) onset + slope hypothesis: the relevant cues are the onset formant values plus the

rate of F2 change over time.

(c) onset + direction hypothesis: the relevant cues are the onset steady state values plus

direction of formant (F1 and F2) movement.

Evidence from these studies has often been contradictory and suggests that results may reflect

the methodology and types of stimuli employed more than the advantage of any one hypothesis.

Gay (1970) used synthesized speech to provide evidence for the onset + slope hypothesis. He

conducted two experiments to examine the perceptual cues needed to identify the American

English diphthongs /ɔi, ai, au/. The first experiment tested the effects of varying formant

frequency transitions on the listeners’ ability to distinguish /ɔi/ from /ai/ and /au/ from /o/

(representing the phonetically diphthongized vowel, [ou]). The continua created for these two

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groups included different onset and offset values for F1-F3. Duration for all sequences was kept

constant at 250 ms and no V1 and V2 steady states were included. The author reports that

listeners used “differences in the course and extent of formant frequency transitions” (Gay, 1970,

p. 77) to distinguish /ɔi-ai/ and /au-o/. However, since stimulus duration was fixed, rate of

formant movement was confounded with onset and offset frequency positions. The second

experiment aimed to tease apart the separate effects of these two cues. Here, the stimuli rated by

listeners in the first experiment as the best examples of /ɔi, ai, au/ were reduced in 10 ms steps

from 250 ms to 100 ms, either at onset or offset. This allowed for variation in the rate of change

of the F2 transitions. The author reports that truncating /ai/ at the offset from 250 ms to 180 ms

yields an /a/ percept. Similarly, the /ɔi/-/ai/ distinction is based on duration and slope: an /ai/

percept requires a longer duration (250 ms) and a greater rate of formant frequency change than

/ɔi/ (180 ms). Thus, he concludes that the F2 rate of change is the primary perceptual cue in

distinguishing between diphthong and vowel and between different diphthongs. Overall,

however, the experiment is not completely successful in evaluating the perceptual effects of

slope alone since slope and duration are confounded here. Still, an important contribution of this

study is the proposal that diphthongs are not concatenations of two simple vowels since their

onset and offset target positions neither match their simple vowel counterparts nor do they serve

to identify the diphthongs. Diphthongs are also not vowel + glide combinations since the mere

presence of gliding is not enough for their identification. Rather, Gay (1970) suggests it is the

glides’ movement through time that characterizes diphthongs.

Bond (1978), using the same synthesized American English diphthongs as Gay (1970), provides

evidence for the onset + offset hypothesis. Here, the duration of onset and offset steady state

portions of /ɔi, ai, au/ was kept constant (onsets = 70 ms and offsets = 40 ms). Glide duration, on

the other hand, varied in 10 ms steps from 140 ms to 0 ms, thus also varying total diphthong

duration from 100 ms to 250 ms Three VV sequences were also synthesized which contained

onset and offset values identical (in duration and formant values) to the diphthongs /ɔi, ai, au/ but

which were separated by a 50 ms silent gap. Participants were asked to identify each stimulus as

one of the three diphthongs or VV sequences. The participants easily and accurately identified

sequences as diphthongs even when no glide was present, calling into question the role of the

glide in diphthong perception. On the other hand, a silent gap and a very long glide tended to

produce VV identification. The author suggests that listeners also use speaking rate information

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in order to identify diphthongs and that these long glide durations and gaps were not deemed

appropriate to a fast speaking rate (which the author believes the participants assumed due to the

short glides presented). However, since the total duration of the diphthongs was not kept

constant, glide duration and total diphthong duration are confounded. Perhaps it is this latter

factor which is causing the VV responses rather than a perceived rate of speech.

Support for the onset + offset hypothesis also comes from Bladon (1985) in a study using natural

speech stimuli. The vowel combinations [ia], [iɛ] and [ie] (i.e. sequences with similar initial

formant values and transition direction but different offsets) and the diphthong [ai] were

recorded by a speaker of British English and subsequently altered to produce stimuli for three

tasks. In the first experiment, the offset portions of [ia], [iɛ] and [ie] were cut at various points,

creating stimuli which ranged in duration from 50 ms to 150 ms in increments of 25 ms Four

phonetically-trained listeners transcribed what they heard. The best responses occurred with

stimuli containing the longest offsets and got progressively worse as offset duration decreased.

This suggests that offsets are crucial for diphthong identification. However, none of the stimuli

used actually exist as diphthongs in English, calling into question the application of these results

to the perception of real diphthongs (Peeters, 1991). In the second experiment, the onset portion

of [ai] was cut. While the actual results for this experiment are not reported, the author

nonetheless concludes that they also support the proposal that transition rate does not determine

diphthong identification. A third experiment compared perception of transitionless diphthongs,

monophthongs and transition-only diphthongs. Here listeners were able to correctly identify the

transitionless diphthongs and the monophthongs 100% of the time based only on V1 and V2

formant values. On the other hand, when identification was based on transition values only, the

same listeners had a 54% error rate. These results point to a reduced role played by the transition

in diphthong identification. However, a careful examination of these last results shows that the

use of mean error rate in identification of transition-only diphthongs may be misleading. In fact,

among these diphthongs, [hɔi] and [hɪə] were correctly identified 70% and 90% of the time,

respectively. Thus, it might be that the perceptual value of the transition differs from diphthong

to diphthong in English.

Gottfried et al. (1993) test the three hypotheses for American English diphthongs in an

experiment which uses natural speech (produced by four untrained speakers of American

English) and statistical pattern recognition to evaluate perception. They created stimuli for /aʊ/,

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/aɪ/, /oʊ/, /ɔɪ/ and /ju/ and varied the consonantal context ([b_d] vs. [h_d]), the stress condition

(test word stressed or unstressed), and speech rate (slow vs. fast). Their results show that the

onset+ offset hypothesis came out slightly on top of the other two (specifying onset and offset

formant values produced a 96% identification rate compared to 94% for the onset + direction

hypothesis and 93% for the onset + slope hypothesis). Clearly, however, all three hypotheses

produce nearly perfect identification rates.

A different approach is taken by Peeters (1991). He argues that what distinguishes vowels,

diphthongs and vowel sequences is not any particular structure or movement pattern since they

all might exhibit movement. Where they differ is in the timing of their movement patterns. Thus,

while both a diphthong and a long vowel may exhibit a similar pattern of movement in two

languages, they will differ in terms of timing (e.g. the proportion allotted to transition may

differ). According to Peeters (1991), these differences are language-specific and what defines the

difference in one language may not do so in another. He tests this hypothesis in a perception

study carried out on listeners of Dutch, English, and German. The study uses the following

synthesized stimuli: (i) the diphthongs /ai/ and /au/; (ii) the diphthongizing vowels /eɪ/ and /oʊ/;

and, (iii) the bi-vocalic (hiatus) sequences /aʔi/ and /aʔo/. For all stimuli, the total duration was

kept constant at 240 ms while the duration of the onset steady state, the glide portion and the

offset steady state varied from 0 to 240 ms. Listeners heard pairs of stimuli and judged which

member was the better example of a diphthong, a long vowel or a bi-vocalic sequence. The pairs

being compared differed in their component durations in 40 millisecond steps. The results

support the hypothesis that different durational patterns are preferred by listeners of different

languages. Thus, English listeners prefer diphthongs with a longer onset (100-120 ms) than their

Dutch or German counterparts (around 60 ms). English listeners also preferred a short offset or

no offset at all; German listeners preferred offsets equal in duration to onsets; and, Dutch

listeners preferred comparatively short offsets but always longer than 20 ms. The differences in

sensitivity to durational patterns may be a function of the vocalic system of each of these

Germanic languages. That is, the degree to which temporal information is used to identify vowel

contrasts by speakers of each language may have perceptual effects (Miller & Grosjean, 1997).

One limitation of this study is that the spectral values for all the stimuli were kept constant across

all the languages. Therefore, these values may have been a confounding factor in the listeners’

judgments. Still, the focus on internal durational organization as both a cue to the perception of

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diphthongs and as the factor which distinguishes diphthongs from one language to another is

supported by acoustic evidence for similar diphthongs in other languages (e.g. Lindau et al.,

1990). The importance of timing is also underscored in Collier and t’Hart (1983) who found that

for Dutch listeners the important cue was the timing of the transition onset in both the genuine

diphthong /ɛi/ (with an optimal transition onset time of 120 ms) and the pseudo diphthong /aj/

(180 ms). These authors found that rate of change and the presence of an offset steady portion

were not necessary for diphthong identification.

3.3.5 Summary

The experimental studies reviewed in this section serve to highlight issues already observed in

the acoustic and articulatory studies. Namely, it appears that, as in production, the perceptual

parameters which listeners exploit in order to discriminate between vocalic sequences may vary

by language. In addition, the type of sequence being heard may also affect perception. On the

other hand, individual differences in the perception of vocalic sequences have not figured

prominently in these perceptual studies. Thus, the matter of individual variation in perception

and its possible link to individual variation in production warrants a closer look.

4 Conclusions

This chapter has reviewed several important studies on vocalic sequences, both for Spanish and

other languages. All in all, it would seem that the bulk of theoretical and experimental evidence

reveals few universals about vocalic sequences. Similar sequences in different languages, as well

as different sequences within a single language, may show both phonetic and phonological

variation. This variation may become evident in differences in phonological patterning and may

be interpreted in terms of features or syllabic/moraic structure. In addition, the acoustic and

articulatory parameters which serve to define these sequences may show cross-linguistic

differences. Similarly, these parameters may vary for different sequences occurring within the

same language. Finally, individual speakers may exploit these parameters to different degrees.

Thus, it is important to test a variety of sequences and to both account for and control individual

and dialectal variation.

In addition, those phonetic parameters which may serve to distinguish between different

sequences in a language (e.g. diphthongs and hiatus in Spanish) may overlap suggesting that very

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finely-grained phonetic detail is required to make the distinction. This fine detail may not be

evident in the acoustics or it may become blurred as speech rate increases or a more casual

speech style is adopted. Moreover, the behaviour of vocalic sequences in different syllable

positions as well as the organization of their component gestures (and perhaps even of individual

muscles) may differ from language to language and sequence to sequence. Still, articulation

studies may be able to provide the fine detail that is not apparent in the acoustics (i.e. articulator

sequencing in different syllable positions; phase relationships between articulators) but which

speakers may exploit in their production and perception. Additionally, individual variation in

articulatory strategy may be missed if the acoustic results do not reflect it. For Spanish, however,

most studies have approached the question of the diphthong-hiatus/exceptional hiatus contrast

from either a theoretical or an acoustic perspective. Some recent studies of Spanish vocalic

sequences propose that the difference between diphthongs and hiatuses as well as the variation

associated with these sequences is rooted in articulatory patterns (Chitoran & Hualde, 2007;

Colantoni & Limanni, 2010). However, these proposals are based on acoustic data as articulatory

data on vocalic sequences in Spanish is lacking.

Finally, the perceptual parameters which identify vocalic sequences and distinguish them from

other sequences appear to vary. However, perception studies provide an important link to

production. For Spanish, this link has largely been established through syllabification and

intuition tasks which have often presented stimuli in written form. A serious limitation of such

studies is that they may reflect schooling (i.e. how well a person learned to syllabify certain

words in school) rather than perception. Thus, testing of the production-perception link for

Spanish vocalic sequences would benefit from a different methodology.

In the next three chapters, the issues of production, perception and variation as they pertain to the

study of Spanish vocalic sequences are examined experimentally. Specifically, three experiments

are carried out to investigate the production and perception of vocalic sequences in Mexican

Spanish through a combination of acoustic, articulation and perception data. In addition to

testing the three hypotheses outlined in Chapter 1 (§4), these three experiments will: (i) add to

existing acoustic data on vocalic sequences in Spanish through the investigation of a variety

other than Argentine or Peninsular Spanish; (ii) complement existing acoustic characterizations

of Spanish diphthongs and hiatuses with articulatory data; (iii) contribute to an understanding of

the link between variation in production and variation in perception of these sequences; (iv)

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provide insight into the prevalence of exceptional hiatuses in a highly diphthongizing variety of

Spanish, and; (v) contribute to research on vowel-vowel coarticulation within and across

syllables. The focus on a single variety of Spanish also allows for an investigation of individual

variation both in the production and perception of the vocalic sequences under study.

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Chapter 3 Acoustic Analysis of Vocalic Sequences in Mexican Spanish

1 Introduction

In the previous chapter, we learned that Spanish diphthongs and hiatuses can be distinguished

acoustically along frequential and temporal parameters. For example, hiatuses are longer than

diphthongs (Aguilar, 1999; Hualde & Prieto, 2002; Chitoran & Hualde, 2007). Diphthongs,

while shorter, devote a larger proportion of the sequence to the transition between the V1 and V2

steady states. This longer, more gradual transition gives diphthongs a smoother F2 slope and a

smaller degree of curvature in the F2 trajectory (Aguilar, 1999). The shorter, faster transition

associated with hiatuses, on the other hand, is reflected in a steeper F2 slope and greater degree

of curvature in the F2 trajectory (Aguilar, 1999). These differences between diphthongs and

hiatuses are generally maintained across speech rate and/or speech style changes (Aguilar, 1997,

1999). Thus, on the surface, the acoustic contrast between diphthongs and hiatuses appears fairly

strong in Spanish (Chitoran & Hualde, 2007).

On the other hand, there is considerable evidence of blurring across the two categories. For

example, the range of duration values for the two categories may show some overlap (Hualde &

Prieto, 2002; MacLeod, 2007) both within speakers and across speakers. In addition, F2 slope

and the proportion of the sequence taken up by the transition may also vary across speakers

(MacLeod, 2007). Two important consequences of this categorial blurring are (i) the

diphthongization of hiatic sequences, and (ii) the production of exceptional hiatuses (where an

expected [jV] sequence is realized as [iV]). While diphthongization of hiatic sequences is

uncontroversially the predominant tendency in Spanish (e.g. Colantoni & Limanni, 2010;

Garrido, 2007), the production of exceptional hiatuses has received considerable attention (e.g

Hualde, 1999; Harris & Kaisse, 1999; Hualde & Prieto, 2002; Cabré & Prieto, 2006; Chitoran &

Hualde, 2007). The phenomenon of exceptional hiatuses is said to be triggered by historic,

prosodic and/or morphological triggers (e.g. Cabré & Prieto, 2006; Chitoran & Hualde, 2007-

see Chapter 2 for a more thorough discussion). However, the occurrence of exceptional hiatuses

may be overstated as a result of the Spanish varieties and the types of sequences which are the

focus of many of these studies. Some researchers, for example, have found that both sequence

duration (Aguilar, 1997, 1999) and transition duration (Lindau et al., 1990) may be sequence-

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specific. They may also be language-specific (Lindau et al., 1990; Peeters, 1991) and speaker-

specific (Cabré & Prieto, 2006; Whitley, 1985). As regards exceptional hiatuses, an emphasis on

Peninsular Spanish speakers (with whom exceptional hiatuses are associated) and on sequences

with the vowel [a] (where the articulatory distance between the non-high vowel and the glide is

maximized and which constitute the bulk of exceptional hiatus cases) may be contributing to an

exaggeration of the ‘hiatus’ characterization of these sequences.

The present chapter aims to address some of these concerns by examining the diphthong-hiatus

contrast in a different variety of Spanish, Mexican Spanish. The study presented here has as its

main objectives (i) to investigate the acoustic properties of diphthongs and hiatuses in Mexican

Spanish, and (ii) to examine the intra- and inter-speaker variation in their production. In relation

to these objectives, the study also examines the effects of speech rate on the categorial and

speaker-specific properties of these sequences and explores whether ‘exceptional hiatuses’ (e.g.

Chitoran & Hualde, 2007) occur in this variety of Spanish. The study tests three hypotheses

linked to these goals. The first hypothesis focuses on the acoustic properties that distinguish

diphthongs from hiatuses in Mexican Spanish.

Hypothesis 1

Diphthongs and hiatuses differ acoustically on temporal and frequential measures.

On the temporal measures, sequence duration is greater for hiatuses than for

diphthongs. Conversely, the proportion of the sequence devoted to the transition

is greater for diphthongs than for hiatuses. On the frequential measures, hiatuses

have more peripheral F1-F2 values than diphthongs. These differences between

hiatuses and diphthongs remain constant under different speech rate conditions.

The second hypothesis looks at the effect of the non-high vowel (V) in the sequence on the

above acoustic properties. This is important because, as mentioned above, most instances of

exceptional hiatuses are found in sequences where [a] is the non-high vowel. An examination of

the phonetic properties of sequences with [a] may explain this occurrence.

Hypothesis 2

The quality of the non-high vowel ([a], [e], or [o]) in the sequence will have

acoustic consequences in both the diphthong and hiatus categories. That is, we

expect to find that diphthongs and hiatuses whose V is [a] to differ significantly

from those with [e] or [o]. For example, we predict that sequences with [a]

(because of the greater tongue/jaw trajectory between [j]/[i] and [a]) will be

longer and/or have shorter transitions than sequences with either [e] or [o].

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The final hypothesis focuses on individual variation in the production of diphthongs and

hiatuses. Because of their dynamic character, the vocalic sequences under study are ideal

candidates for variability, both within and between speakers. This variability may be evident in

the production of diphthongs (e.g. McDougall 2004, 2006; MacLeod, 2007) as well as in the

realization of the diphthong-hiatus contrast (Colantoni & Limanni,, 2010). The focus on a single

variety of Spanish as well as on speakers who are matched on gender and education level permits

a detailed investigation of individual differences in the production of these sequences.

Hypothesis 3

Individuals may use distinctive patterns of articulation to produce diphthongs and

hiatuses and to achieve the diphthong-hiatus contrast. These distinctive patterns

are reflected acoustically in the temporal and/or the frequential measurements and

may give rise to sequences whose category membership is not clear-cut, as in the

case of exceptional hiatuses.

These hypotheses are tested in an experimental study whose methodology is outlined in §2

below. The results of the acoustic analysis are given in §3 and evaluated and discussed in §4. A

brief conclusion given in §5 ends the chapter and sets the stage for the next two experimental

chapters.

2 Experimental Methodology

2.1 Participants

All ten of the participants described in Chapter 1, §4.1 participated in this experiment. These

participants will be referred to here as AA, AM, AN, CG, DH, KR, LG, LL, MM, and MV.

Participants were compensated for taking part in the experiment.

2.2 Stimuli

The target sequences for this experiment were diphthongs in stressed syllables and hiatuses

where the stressed vowel was the first member of the sequence. The experimental materials were

designed to elicit production of these target sequences at two different speech rates: a

normal/slower rate and a faster but still comfortable (i.e. pronounceable) rate. The stimuli set

consisted of 40 real words (Appendix 1). Of these 40 words, 20 were distractors (of interest for

another experiment), 5 of which were used in the practice sentences for the task and 15 of which

contained simple vowels ([a,e,i,o,u]). The remaining 20 words included the following

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combinations of the target sequences: (i) hiatus [í.a], [í.e], [í.o] and (ii) diphthong: [já], [jé],

[já]27

. Position in the word and stress were not tested. Therefore, all diphthongs appear in the

first syllable of the target words and this first syllable is always stressed. For hiatuses, the

stressed high vowel itself is in the first syllable.

The number of diphthong tokens is higher than the number of hiatus tokens since the diphthong

category also included tokens which have been identified as possible exceptional hiatuses in

other varieties of Spanish (Hualde, 1999; Hualde, 2005; Chitoran & Hualde, 2007). These were

included in order to test whether this category of sequences is present in Mexican Spanish. If, as

hypothesized, these sequences are indeed produced in this variety, we expect to find instances of

[i.á], [i.é] and [i.ó].

Following Aguilar (1999, p.59), the consonants preceding the target sequences were ‘diffuse’

consonants: labials, dentals or alveolars. Due to lexical gaps, however, it was not always possible

to control for the following consonant. The target words were embedded in the carrier sentence

Digo X para ti “I say X for you” and prepared for presentation to the participants for a reading

task. Because the target words consisted of 2 syllables, the sentences contained 7 syllables.

2.3 Tasks and Procedures

Recordings took place in the Communications Functions Lab, Toronto Rehabilitation Institute

(Department of Speech-Language Pathology, U of T). The participants were seated in a sound-

attenuated booth with an Isomax E6 Omnidirectional flat frequency microphone with the ear set

placed over the participants’ left ear and the boom placed just back from the corner of their

mouth. The recordings were made using a Marantz PMD670 Professional portable solid state

recorder with a sampling rate of 48 kHz.

The participants were recorded as they read words containing the target sequences and

distractors. The list of sentences was randomized and presented to the participants on a computer

monitor using DirectRT presentation software (Empirisoft Corp.). Instructions were provided to

27 Although data was collected for both velar and palatal series of sequences, as well as for both rising and falling sequences only

the rising palatal series is analyzed here since it is the most relevant for the hypotheses being tested. Within this series, data was

also collected for diphthongs in unstressed syllables but this is not included here. Therefore, the number of tokens analyzed

reflects only the rising palatal sequences in stressed syllables. The overall total of tokens recorded (including all types of

sequences as well as distractors and practice words) totaled 3720.

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the participants both in written form (on the computer monitor) and orally. The experimenter was

always available to provide clarifications whenever necessary. Speech rate was controlled by a

visual metronome which consisted of a flashing green light on the computer monitor above the

location where the sentences appeared. The stimuli were presented to the participants according

to the following procedure. The test sentence appeared first on the computer monitor, and then a

red light flashed above the sentence twice at controlled intervals. The purpose of the red light

was to establish the speech rate that the participant was expected to use for that block of

sentences when the green light flashed. Thus, the red light represented the familiarization mode

and the green light the testing mode. The participant, at this point, simply looked at the sentence

and the flashing light. After the red light had flashed twice, a warning beep (a sine wave, 1000

ms in length) sounded indicating to the participant that the green light was about to appear and

that she was to get ready to read out loud. The participants read the sentences at two rates of

speech. The first reading was at a normal/slow rate, with a 1.5 second interval between flashing

green lights. This converts to a speech rate of approximately 4.7 syllables/second. The second

reading was at a faster but still comfortable rate (with a 1.1 second interval between flashing

green lights). This second speech rate is approximately 6.4 syllables/second. These speech rates

were established through testing of various rates in the course of three pilot studies.

For the reading task, participants were instructed to try to synchronize the first word of the

carrier sentence with the flash of the green light and to finish reading the sentence before the

next flash appeared. Five practice trials for each speech rate were used to familiarize the

participants with the task. The participants repeated each practice and test sentence 3 times

consecutively in each trial. Therefore, each target sentence was produced three times at two

speaking rates, resulting in a total of 40*3*2= 312 utterances per participant. Of these, only the

utterances containing the target vowel sequences were analyzed for the present study: 120 per

participant for a total of 1200. The entire experiment lasted approximately one hour. To avoid

fatigue, the participants were given short breaks after every 12-13 trials. In addition, after

completion of each trial, they were asked whether they were ready to proceed with the next trial

or if they needed a pause.

The syllables/second results obtained for each speaker at each speech rate are given in Table 1.

They show that, overall, the mean number of syllables/second was higher than expected for Rate

1(on average, 1 syllable/second faster). For Rate 2, the number of syllables/second more closely

71

matched the expected rate. The individual numbers also point to a great deal of individual

variation in speech rate.

Table 1. Means and SDs of syllables per second produced by Speakers, by Speech Rate

Rate1 Rate2

%increase Speaker syllable/second SD syllable/second SD

AA 5.2 0.23 5.5 0.26 5.8%

AM 4.9 0.36 5.6 0.32 14.3%

AN 5.7 0.18 5.9 0.35 3.5%

CG 6.5 0.17 6.9 0.19 6.2%

DH 6.6 0.30 7.3 0.27 10.6%

KR 6.0 0.25 6.4 0.27 6.7%

LG 6.4 0.29 6.8 0.25 6.3%

LL 6.3 0.42 7.2 0.36 14.3%

MM 6.4 0.19 6.9 0.27 7.8%

MV 5.0 0.33 5.8 0.21 16.0%

GROUP MEAN 5.9 0.67 6.4 0.71 9.1%

Table 1 highlights that, regardless of whether or not they matched the expected rate, all speakers

increased their speech rate from Rate 1 to Rate 2 and a Repeated-Measures ANOVA confirms a

significant effect of Rate (F(1,9) = 49.81, p=0.000). This can be interpreted as evidence that all the

participants conformed to the task requirements and all can be included in the analyses to follow.

However, it is important to point out that, since all the speakers produced more syllables/second

than predicted for Rate 1, the percentage increase from Rate 1 to Rate 2 was smaller than the

expected 36%. In fact, the increase was less than 20% for all the speakers and for some (e.g. AA

and AN) the increase was negligible.

2.4 Measurements and Analyses

Acoustic studies of diphthongs and hiatuses have generally characterized these sequences as

consisting of three portions: the first vowel target (V1), the second vowel target (V2) and the

transition (T) between V1 and V2. The assumption of this tripartite organization has been useful

in identifying the acoustic properties which distinguish diphthongs from hiatuses. However, this

assumption potentially results in difficulties in measurement, especially since V1 and V2 steady

states may not always be clear for diphthongs (Aguilar, 1999; Kinoshita & Otanai, 2006).

Aguilar (1999) avoids these difficulties by employing a dynamic analysis procedure (a 14-order

LPC analysis performed every 10 ms with a 20 ms window) rather than the traditional

segmentation procedure (V1-T-V2) to model formant trajectories (F1 and F2).

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The present study follows the tradition of previous acoustic experiments in considering both

frequential and temporal measurements of the target sequences. In terms of how and where to

take these measurements, a middle ground is taken. With frequential measurements, the view

that diphthongs may not always be neatly broken up into readily measurable segments

identifiable as V1-T-V2 is taken. Thus, on these measures, a more dynamical approach is used.

However, for the temporal measurements, both the duration of the entire sequence and the

duration of the transition portion are considered for the following reasons. First, the duration of

the entire sequence allows a comparison between diphthongs and hiatuses. Second, where the

difference in overall duration between diphthongs and hiatuses is not statistically significant (as

may be the case for some speakers, e.g. Colantoni & Limanni, 2010) the transition duration may

still show differences between them. In those cases, the transition portion would still be

measurable even where a V1 and/or a V2 steady state are not present or are difficult to measure.

To prepare the data for measurement and analysis, the carrier sentences were extracted from the

recordings. Then the words containing the target sequences were extracted from these sentences

and saved in separate sound files. Next, word tokens were coded in Excel as Diphthong or Hiatus

as per their expected production (Sequence Type). The independent variables were coded as

follows:

(i) Non-high Vowel (V): [a], [e], [o].

(ii) Speech Rate: Rate 1 and Rate 2.

Subsequent to coding, temporal (§2.4.1) and frequency (§2.4.2) measurements were taken using

Praat (Boersma & Weenink, 2010).

2.4.1 Temporal Measurements

For these measurements, demarcations made on the individual sound files were used to create

annotated Textgrid files in Praat. These files were then used to run scripts which calculated the

durations and wrote the output to an Excel file. The measurements used include:

(i) duration (in ms) of the entire vocalic sequence.

(ii) duration (in ms) of the sequence transition.

For the first measurement, the onset and offset of each sequence were determined using

information from both the waveform and the spectrogram. Specifically, increases in F1 and in

73

intensity were used to determine the sequence onset while a decrease in F1 was used to mark the

sequence offset. The transition duration was measured using criteria outlined in Chitoran (2002)

and Colantoni & Limanni (2010), based on guidelines established in Ren (1986, p. 74). Namely,

the transition onset was determined as the highest F2 before a drop of around 20 Hz. The offset

of the transition was marked as the point where a steady state for V2 began or in cases where no

steady state was detectable, the point where the following consonant began. Figure 1 illustrates

the measurements for sequence and transition duration.

Figure 1. Spectrogram of a token of [jó] produced by speaker CG, showing the boundaries

for sequence and transition duration measurements

These raw duration measurements were then normalized as follows. The sequence duration was

normalized using a z-transformation procedure known as the Lobanov method (cited in Wang,

2007, p. 90) where each participant’s mean sequence duration score ( X calculated across all

tokens for that speaker) was subtracted from her raw score (x, for the individual token) and

divided by her standard deviation (SD, calculated across all tokens for that speaker). The formula

for this procedure is as follows:

74

(19) Lobanov method normalization: z = SD

Xx

For example, Speaker AA had a mean sequence duration score of 187.07 ms (SD=55.52 ms).

Her score for the word bienes (Rate 1, repetition 1) was 161.62 ms Using these numbers in the

above formula, the normalized score (z) for this token of bienes is -0.46, approximately one-half

SD shorter than her mean sequence duration across all tokens (which now represents the zero

point): -0.46 =52.55

07.18762.161.

This normalization allows for the comparison of vocalic sequences across speakers regardless of

individual variation in speech rate. The transition duration, on the other hand, was normalized as

a proportion of the raw duration of the sequence (e.g. Lindau et al., 1990; Aguilar, 1997;

Colantoni & Limanni, 2010). This allows for the comparison of transition durations in sequences

of different durations.

2.4.2 Frequency Measurements

A second script was applied to the sequence duration Textgrid files created in Praat. This script

first divided the total duration of each sequence into 10 equal intervals (McDougall, 2004, 2006;

McDougall & Nolan 2007), as shown in Figure 2. The script then calculated the mean

frequencies of F1 and F2 at the midpoint of each interval and wrote the output to an Excel file

for analysis. This procedure preserves the dynamical aspect of each formant contour while it

time-normalizes each formant contour so that the frequential properties of sequences of different

durations can be easily compared. The frequencies were checked for any clearly odd numbers

and in those cases, frequencies were measured manually.

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Figure 2. Spectrogram of a token of [jó] produced by speaker CG, showing the 10 intervals

where F1 and F2 frequency measurements were made

Prior to analysis, the Hertz values for all frequencies were transformed to Bark using the

following formula proposed by Traunmüller (1990) (cited in Wang, 2007, p. 88; Hayward, 2000,

p. 142):

(20) Bark = [(26.81 × F) / (1960 + F)] – 0.53, where F = the formant frequency in Hertz

The shape and size of each individual participant’s vocal tract influences these formant values.

Thus, formant values for the same sequence are expected to differ according to participant. The

Bark transformation (a ‘vowel-intrinsic’ technique which uses values from single vowel tokens),

however, may not be the best technique for equalizing the effects of vocal tract variation. In fact,

some authors (e.g. Adank et al., 2004; Flynn, 2011) have found that ‘vowel-extrinsic’ techniques

which use information from multiple vowel tokens (i.e. the Lobanov method cited above)

perform better at minimizing inter-speaker variation.28

Unfortunately, because of the large

number of points measured for each sequence, the z-normalization procedure could not be

carried out. Such a procedure has proved useful for normalizing simple vowel frequencies when

28 All methods tested, however, were found to perform better than raw Hertz values (Adank et al., 2004; Flynn, 2011).

76

measurements are taken either at a single point (i.e. vowel mid-point) or at most at 3 relatively

steady points (Wang, 2007, p. 89). However, when this procedure was applied to the data in the

present study, it distorted the properties of the formant contours of the sequences. This distortion

creates a problem since, for this experiment, we are interested in the relative shape of the formant

contours of these sequences, rather than any absolute formant values. In addition, this type of

frequency normalization is often used to control for gender differences. Thus, because all the

participants were women of similar size and height, variation due to vocal tract size is at least

partially controlled for.

Results for all the above measurements were evaluated statistically29

using Excel and Minitab 14,

with p level set at .05. For these analyses, only the expected realizations (Sequence Type) of the

sequences are used rather than the actual production of the sequences (i.e. those cases where

Diphthong may be realized as Hiatus or cases where Hiatus is realized as Diphthong). The

purpose of this was to avoid using a subjective measure, such as auditory determination by the

author or other listener, to decide if a sequence is realized as a diphthong, hiatus or exceptional

hiatus (e.g. Hualde & Prieto, 2002; Face & Alvord, 2004). Nevertheless, to test Hypothesis 3,

we also needed to determine how well the sequences fit into their expected categories based on

the acoustic parameters (i.e. temporal and frequential) described above and whether ambiguous

sequences exist for this variety of Spanish. Specifically, we were interested in identifying

instances of expected hiatuses produced as diphthongs, and, especially, instances of expected

diphthongs produces as hiatuses (i.e. exceptional hiatuses). Normally, this determination would

be based on auditory discrimination on the part of the researcher or on the syllabification

intuitions of the participants or other native speakers (e.g. Hualde & Prieto, 2002; Face &

Alvord, 2004). However, previous experience, schooling and expectations of how words should

29 Before the data was submitted to statistical analyses, tests for normality of distribution and for equality of variances were

carried out to determine whether the data conformed to the requirements of parametric analyses. Anderson-Darling (AD) tests for

normality of distribution show that both Diphthong and Hiatus categories are normally distributed in terms of normalized

sequence duration and %Transition at both speech rates tested (i.e. p > 0.05 in all cases). The p values obtained are as follows:

(i) normalized duration: Diphthong (Rate 1: p=0.313; Rate 2: p=0.701); Hiatus (Rate 1: p= 0.958; Rate 2: p=0.122), and (ii)

%Transition: Diphthong (Rate 1: p=0.503; Rate 2: p=0.732); Hiatus (Rate 1: p=0.502; Rate 2: p=0.699).

In addition, there were no significant differences between Diphthong and Hiatus at either rate of speech in terms of variance.

Thus, Bartlett’s test values were not significant (i.e. p > 0.05 in all cases, although they approach significance for normalized

duration): for normalized duration, p=0.052; for %Transition, p=0.532.

The frequency measurements, on the other hand, deviated from a normal distribution at several of the time points sampled. Thus,

for those measurements only the equality of variances requirement was met. The results of the Levene’s test (appropriate for any

continuous distribution) show no significant difference in variance between Diphthong and Hiatus in F1 and F2 at either speech

rate: (i) Rate 1 (F1: p=0.151; F2: p= 0.704) and (ii) Rate 2 (F1: p=0.670; F2: p=0.568).

77

be pronounced may affect this judgment (e.g. Docherty, 2003). In addition, repeated exposure to

the same sequences may result in an increased tendency to classify those sequences as

diphthongs (Gili Favela & Bertinetto, 1998). Thus, a more objective way of assigning a surface

category is desirable. The technique used in the present study is described next.

2.4.3 Discriminant Analysis

We use Discriminant Analysis (DA), a multivariate statistical technique used to decide category

membership based on certain measurable predictors (Grimm & Yarnold, 1995). The usefulness

of this technique in phonetics is supported by research which suggests that Discriminant

Analysis is useful in identifying perceptually distinctive contrasts (Port & Crawford, 1989; Faber

& DiPaolo, 1995; Morrison, 2006). An added benefit of DA, especially for the present

experiment, is that the technique works with unequal sample sizes as long the sample size of the

smallest group (in this case, Hiatus) exceeds the number of predictor variables by a factor of 4 or

5 (a condition which this experiment meets). In the present study, category membership is

defined as either Diphthong or Hiatus and the predictors are the durational and frequential

parameters identified in previous sections: normalized sequence duration, proportion of sequence

taken up by the transition, and time-normalized F1-F2 measurements.

The statistical program used to carry out the DA analysis (Minitab 14) uses a measure of squared

distance between groups to classify all observations (i.e. a Mahalanobis distance, D2).

Specifically, a token is classified as Diphthong or Hiatus depending on the degree of difference

of its squared distance to the group mean for the two groups. Any Diphthong tokens

misclassified as Hiatus may be considered cases of exceptional hiatus. Similarly, any Hiatus

tokens misclassified as Diphthong can be considered diphthongized. In all cases, a cross-

validation procedure available in Minitab was also used to assess the classification probabilities

of each token and to correct the error rates.

To test the validity of the Mahalanobis’ distance30

as the criterion for discrimination between the

two categories (Diphthong and Hiatus) an F statistic was calculated and assessed against the

critical F-value associated with the 5% significance level, using the following formula (based on

Gardiner 1997: 316):

30 A test of significance for the discriminant functions is not available in Minitab.

78

(21)

Where: = number of samples for Diphthong

= number of samples for Hiatus

= number of predictors

= the Mahalanobis distance measure

The degrees of freedom for the above equation were calculated as follows: df1=p and df2=

.

The results of all analyses are reported next.

3 Results

3.1 Sequence Duration

In this section we examine the duration of the sequences under study to determine whether there

is a difference on this measure between Diphthong and Hiatus. In interpreting the normalized

duration values, a positive number reflects a duration which is greater than the mean duration for

all sequences (represented by the zero point) while a negative number reflects a duration which

is smaller than the mean duration for all sequences. For both raw and normalized scores, we

predict that the duration values for hiatuses will be greater than the duration values for

diphthongs. A summary of the descriptive statistics for both raw and normalized sequence

durations is provided in Table 2.

Table 2. Means and SDs of raw and normalized sequence duration for Diphthong and

Hiatus, by Speech Rate

Rate 1 Rate 2

Measurement Sequence Type Mean SD Mean SD

raw duration Diphthong 137.86 42.76 121.34 40.32

Hiatus 177.73 36.26 165.74 36.71

normalized

duration

Diphthong 0.34 0.88 -0.16 0.83

Hiatus 1.57 0.72 1.19 0.60

To illustrate the importance of normalizing sequence durations, we examine the raw data first.

The differences between Diphthong and Hiatus for the group are illustrated in Figure 3, where

we observe a clear durational difference between Diphthong and Hiatus at both speech rates.

79

Sequence Type

Du

rati

on

(m

se

c.)

HiatusDiphthong

200

150

100

50

0HiatusDiphthong

Rate = 1 Rate = 2

*Bars are One Standard Error from the Mean

Figure 3. Bar chart of mean sequence duration (ms) by Sequence Type and Speech Rate

A repeated-measures ANOVA (Table 3) with within-subject factors Rate (1 vs. 2) and Sequence

Type (Diphthong vs. Hiatus) confirms our observations31

. First, we find a significant effect of

Sequence Type. Thus, the mean duration of Hiatus is significantly longer than the mean duration

of Diphthong. We also observe a significant Rate effect. However, the Rate*Sequence Type

interaction is not significant. Therefore, although the durations of both Diphthong and Hiatus

decrease as speech rate increases, the category difference remains constant at the two rates of

speech.

Table 3. ANOVA table for differences between Diphthong and Hiatus in raw sequence

duration (ms), by Speech Rate

Source F(df term, df error) p

Main effects Sequence Type F(1,9)=119.80 0.000

Rate F(1,9)=15.14 0.004

Interaction Sequence Type*Rate F(1,9)=0.88 0.372

Other Speaker F(9,27)=16.41 0.000

31 In this and all subsequent ANOVA tables, significant p-values are shaded gray.

80

When we look at the individual data in Figure 4, we see that all the speakers follow the same

pattern32

. That is, for all speakers Hiatus is longer than Diphthong and this difference remains

constant across speech rates. The data also serves to point out that, for most speakers, both

Diphthong and Hiatus are shorter at Rate 2 than they are at Rate 1. However, this durational

difference according to speech rate does not apply to all the speakers, especially for Hiatus

sequences. For example, speakers KR and MM had virtually identical mean durations for

hiatuses at Rate 1 and Rate 2. Speaker AA, on the other hand, produced longer (rather than

shorter) hiatuses at Rate 2. Thus, even though all the participants were found to have increased

their speech rate in terms of overall syllables per second (refer to Table 1, §2.3) some of them

appear to have maintained a constant rate of speech at the sequence level.

The individual data also points to variability in the duration of Diphthong and Hiatus. These

differences are highlighted in Figure 4 and are mirrored in a significant Speaker effect in the

analysis (Table 3). That is, some speakers have mean Hiatus durations which are similar to or

smaller than the mean Diphthong durations of other speakers (in agreement with previous

research, e.g. Hualde & Prieto, 2002). In particular, Speakers AA and AM have mean Diphthong

durations that are approximately equal to or greater than the mean Hiatus durations of almost all

the other speakers. This highlights the necessity to normalize the raw data in order to adequately

compare Diphthong and Hiatus durations across speakers.

32 The individual and group means and standard variations are found Appendix 2 (Table A2.1)

81

Du

rati

on

(m

se

c.)

200

100

0

200

100

0

21 21

Rate 21

200

100

0

21

A A A M A N C G

DH KR LG LL

MM MV

Sequence Type

Diphthong

Hiatus


Figure 4. Bar chart of mean sequence duration (ms) by Sequence Type, Speech Rate and

Speaker

The normalized sequence duration data (given in Table 2 and illustrated in Figure 5) suggest that

the Hiatus category is associated with a relatively large positive number at Rate 1 and a smaller

positive number at Rate 2. The Diphthong category, on the other hand, hovers around zero (i.e.

the mean duration of all sequences). These sequences are associated with a small positive

number at Rate 1 and with a small negative number at Rate 2. An increase in speech rate then

results in Hiatus moving closer to zero and Diphthong moving away from zero in a negative

direction. In other words, both the Hiatus and Diphthong categories get shorter as speech rate

increases. This pattern of durational differences is maintained across speech rates and is the same

as what was found with the raw data.

82

Sequence Type

Du

rati

on

(n

orm

aliz

ed

)

HiatusDiphthong

2

1

0

-1

-2HiatusDiphthong

Rate = 1 Rate = 2


Figure 5. Bar chart of mean sequence duration (normalized) by Sequence Type and Rate

The results for the repeated-measures ANOVA (Table 4) also mirror the results found in the raw

data. Thus, we find significant main effects of Sequence Type and Rate. The Rate*Sequence

Type interaction, however, is not significant. That is, although both Diphthong and Hiatus are

shorter at Rate 2 than at Rate 1, Diphthong is shorter than Hiatus at both rates of speech. The

overall difference between Diphthong and Hiatus is 1.23 at Rate 1 and 1.34 at Rate 2 (Table

A2.1, Appendix 2).


(normalized), by Speech Rate



Rate F(1,9)=19.79 0.002


Other Speaker F(9,27)=0.27 0.970

83

Figure 6 shows that all speakers behave in this manner, even those who deviated from this

pattern on the raw durations33

. Thus, because normalization eliminates the variance due to

individual speech rate differences, we no longer find any overlap in global Diphthong and Hiatus

duration between speakers and, statistically, there is no significant Speaker effect now (Table 4).

However, individual variation in the realization of Diphthong and Hiatus is preserved. Therefore,

for some speakers the durational difference between Diphthong and Hiatus is larger than for

others. For example, MV appears to have comparatively long diphthongs at Rate 1, resulting in

the smallest durational difference between Diphthong and Hiatus of all the speakers (at 0.26,

Table A2.2, Appendix 2). Speakers CG, DH and KR, on the other hand, produced the largest

durational differences between Diphthong and Hiatus at both speech rates.

Du

rati

on

(n

orm

aliz

ed

)

2

0

-2

2

0

-2

21 21

Rate 21

2

0

-2

21

A A A M A N C G

DH KR LG LL

MM MV

Sequence Type

Diphthong

Hiatus


Figure 6. Bar chart of mean sequence duration (normalized) by Sequence Type, Speech

Rate and Speaker

33 The individual and group means and standard variations are found in Appendix 2 (Tables A2.2).

84

3.1.1 Vowel Effects on Sequence Duration

Here, we examine whether the non-high vowel (V) in the vocalic sequences under study has any

effect on the duration of the sequence and, if so, whether the effect is different for diphthongs

and hiatuses. Our prediction is that sequences where V= [a] will be longer than those where V=

[e] or [o]. The group descriptive statistics for this section are summarized in Table 5.

Table 5. Means and SDs for sequence duration (normalized) of Diphthong and Hiatus, by

Sequence Type, Rate and V

Sequence Type

Rate 1 Rate 2

Vowel Mean SD Mean SD

Diphthong

[a] 0.77 0.80 0.17 0.69

[e] 0.08 0.89 -0.34 0.93

[o] 0.05 0.67 -0.39 0.66

Hiatus

[a] 1.85 0.74 1.29 0.57

[e] 1.29 0.55 0.93 0.60

[o] 1.27 0.60 1.24 0.59

The overall data (Figure 7 and Table 5)34

suggests a slightly different pattern of V effects for

diphthongs and hiatuses. For diphthongs, we observe that at both speech rates sequences with [a]

are noticeably longer that those with [e] or [o], while the differences between sequences with [e]

and [o] are relatively small. For hiatuses, on the other hand, the above pattern is found only at

Rate 1. At Rate 2, hiatuses with [e] are shortest and little difference is observed between hiatuses

with [a] and those with [o].

34 The individual and group means and standard variations for this section are found in Appendix 2 (Tables A2.3 through A2.5).

85

Du

rati

on

(n

orm

aliz

ed

)

V [o][e][a]

2

1

0

-1

-2[o][e][a]

Rate = 1 Rate = 2

Sequence Type

Diphthong

Hiatus


Figure 7. Bar chart of mean duration (normalized) by Sequence Type, Speech Rate and V

A repeated-measures ANOVA with factors Rate (1 vs. 2), Sequence Type (Diphthong vs. Hiatus)

and V ([a] vs. [e] vs. [o]) yielded significant main effects for all the main factors tested. Among

the interactions, only Rate*V was significant.

Table 6. ANOVA table for differences between Diphthong and Hiatus in sequence

duration (normalized), by Speech Rate and V


Main effects

Sequence Type F(1,18)=9.43 0.000

Rate F(1,18)=16.37 0.003

V F(2,18)=23.80 0.000

Interactions

Rate*Sequence Type F(1,18)=1.46 0.258

Rate*V F(2,18)=8.16 0.003

Sequence Type*V F(2,18)=2.30 0.129

Rate*Sequence Type*V F(2,18)=2.67 0.097

Other Speaker F (9,99)= 0.33 0.945

The results for Sequence Type and Rate are as expected: hiatuses are longer than diphthongs and

all sequences are longer at Rate 1 than at Rate 2. The results for the main effect of V confirm that

[a], [e] and [o] have different effects on sequence duration. Post-hoc comparisons (Bonferroni)

between levels of factor V show where these V effects occur.

86


sequence duration (normalized), by Speech Rate and V

Vowel vs. t-value p

V

[a] [e] -11.91 0.000

[a] [o] -10.67 0.000

[e] [o] 1.23 0.702

Rate*V

[a] [e] -9.92 0.000

Rate1 [a] [o] -10.22 0.000

[e] [o] -0.30 1.000

[a] [e] -6.92 0.000

Rate2 [a] [o] -4.88 0.002

[e] [o] 2.04 0.835

Rate*Sequence Type*V

Diphthong

Rate1

[a] [e] -9.03 0.000

[a] [o] -7.46 0.000

[e] [o] -0.28 1.000

Rate2

[a] [e] -6.80 0.000

[a] [o] -5.87 0.000

[e] [o] -0.49 1.000

Hiatus

Rate1

[a] [e] -3.41 0.045

[a] [o] -3.47 0.035

[e] [o] -0.06 1.000

Rate2

[a] [e] -2.19 1.000

[a] [o] -0.35 1.000

[e] [o] 1.59 1.000

The above comparisons reveal that sequences with [a] are significantly longer than those with

either [e] or [o]. The difference between [e] and [o], however, is not significant. The Rate*V

interaction found above would seem to suggest that these differences among levels of V should

occur only at one of the speech rates. The post-hoc comparisons for all levels of Rate*V,

however, show that the differences between [a] and [e] and [a] and [o] hold at both speech rates.

These results do not coincide with our observations of what happens to Hiatus at Rate 2. Further

analysis reveals that, in fact, when Diphthong and Hiatus categories are considered separately,

the effects of V on Rate 2 hiatuses are not significant. Thus it appears that differences between

Diphthong and Hiatus may be influencing the Rate*V interaction even though no significant

Rate*Sequence Type*V interaction is found.

To summarize, based on the above results, we can tentatively propose the following hierarchies

of sequence duration according to Sequence Type, Speech Rate and V:

87

(i) Diphthongs (all) and Hiatuses (Rate 1): [a]>[e],[o]

(ii) Hiatuses (Rate 2): [a]=[e]=[o]

Although the group data contains no significant Speaker effect (Table 6), we do see some

individual variation (Figure 8, Tables A2.3-A2.5, Appendix 2), especially with the hiatuses. With

Diphthong, speakers followed the durational differences identified above. In other words, all the

speakers produced longer diphthongs with [a] at both speech rates, with the difference being

greater at Rate 1. In addition, speakers MM and MV produced comparatively long [a] diphthongs

at Rate 1, suggesting a hiatus pronunciation of [já] sequences. In fact, their diphthongs with [a]

(Figure 8) are either comparable to (in the case of MM) or longer than (in the case of MV) their

hiatus counterparts.

Du

rati

on

(n

orm

aliz

ed

)

2

0

-2

2

0

-2[o][e][a] [o][e][a]

V [o][e][a]

2

0

-2[o][e][a]

A A A M A N C G

DH KR LG LL

MM MV

Sequence Ty pe

Diphthong

Hiatus

Rate = 1

Du

rati

on

(n

orm

aliz

ed

)2

0

-2

2

0

-2[o][e][a] [o][e][a]

V [o][e][a]

2

0

-2[o][e][a]

A A A M A N C G

DH KR LG LL

MM MV

Sequence Ty pe

Diphthong

Hiatus

Rate = 2

Figure 8. Bar chart of mean duration (normalized) by Sequence Type, V and Speaker:

Rate 1 and Rate 2

With Hiatus, we find more variability. Although less obvious than with Diphthong, most

speakers (except CG and MV) do adhere to the overall pattern of longer [a] hiatuses at Rate 1. At

Rate 2, differences due to V are less obvious for most speakers, also in line with the overall data.

A couple of speakers show distinct patterns. For example, DH produces short hiatuses with [e] at

both speech rates. This suggests a diphthongized production of the word ríen. MV, on the other

88

hand has comparatively short [o] hiatuses at Rate 1, suggesting a diphthongized production of

ríos.

It’s also important to note that while the differences between Diphthong and Hiatus sequences

were significant for all three non-high vowels, the amount of difference varies according to V

(Tables A2.3-A2.5, Appendix 2). Thus, although sequences with [a] tend to be longest overall,

the difference between [já] and [í.a] is smallest at just over 1 SD (1.08 at Rate 1; 1.12 at Rate 2).

The differences between [jé] and [í.e] (1.21 at Rate 1; 1.28 at Rate 2) and between [jó] and [í.o]

(1.22 at Rate 1; 1.63 at Rate 2) are slightly greater. Thus, diphthong and hiatuses where V= [a]

are closer to each other in duration than their counterparts with [e] or [o].

3.2 Transition Duration

We turn now to our second temporal measurement. Transition duration was measured according

to the criteria outlined in §2.4. As with sequence durations, these raw measurements were

normalized in order to account for sequences and transitions of different durations. In this case,

the sequence transition (T) duration was normalized as a proportion (reported as a percentage,

%Transition) of the raw duration (in ms) of the sequence (e.g. Lindau et al., 1990; Peeters, 1991;

Colantoni & Limanni, 2010) since we are interested only in the relative duration of the transition

rather than its absolute duration. This is because the relative duration of the transition may be

maintained or increased as speech rate changes (i.e. by manipulating the duration of the other

portions of the sequence) while the absolute duration of the sequence is generally expected to

change according to speech rate (as we saw in §3.1). On this measure, we predict that diphthongs

will have a greater %Transition than hiatuses. The descriptive statistics for this measure are

summarized in Table 8.

Table 8. Means and SDs of %Transition for Diphthong and Hiatus, by Speech Rate

Rate 1 Rate 2

Measurement Sequence Type Mean SD Mean SD

%Transition Diphthong 47.34 12.97 47.49 13.73

Hiatus 34.21 8.35 35.71 7.51

As predicted, the transition takes up a larger proportion of the sequence in Diphthong than it

does in Hiatus (Table 8 and Figure 9)35

.

35 The individual and group means and standard variations for this section are found in Appendix 2 (Table A2.6).

89

Sequence Type

%Tra

nsit

ion

HiatusDiphthong

100

75

50

25

0HiatusDiphthong

Rate = 1 Rate = 2


Figure 9. Bar chart of mean %Transition by Sequence Type and Speech Rate

In the group data, we find that the transition makes up approximately 50% of the sequence for

diphthongs while for hiatuses that number is roughly 35%. Interestingly, these figures remain

stable across speech rates for both Diphthong and Hiatus. That is, %Transition does not increase

significantly in either the Diphthong or the Hiatus category even though the duration of the

sequence decreases at the faster speech rate. Accordingly, a repeated-measures ANOVA (Table

9) finds a significant main effect of Sequence Type. However neither Rate nor the Sequence

Type*Rate interaction were significant.


Speech Rate



Rate F(1,9)=0.56 0.474



An examination of the individual data shows that all of the speakers follow these patterns (Figure

10, Table A2.6, Appendix 2). That is, Diphthong has a greater %Transition at both rates of

speech for all speakers. Also, for most speakers the proportion of the sequence devoted to the

90

transition changes only minimally at the faster rate of speech (Rate 2) for both Diphthong and

Hiatus. On the other hand, there is some variability in the amount of difference between

Diphthong and Hiatus. For example, for Rate 1 this difference ranges from a low of 3.22% (for

CG) to a high of 21.75% (for KR). For Rate 2 the range is from 4.11% (for CG again) to 16.46%

(for LG). This variability is responsible for the significant Speaker effect seen in the data.

%Tra

nsit

ion

100

50

0

100

50

0

21 21

Rate 21

100

50

0

21

A A A M A N C G

DH KR LG LL

MM MV

Sequence Type

Diphthong

Hiatus


Figure 10. Bar chart of mean % Transition by Sequence Type, Speech Rate and Speaker

3.2.1 Vowel Effects on Transition Duration

The effects of non-high vowels (V) on %Transition are examined next. On this measure, we

predict that sequences with [a] will have a smaller %Transition than sequences with [e] or [o]. A

summary of the descriptive statistics for the group are given in Table 1036

.

36 The individual means and standard variations for this section are found in Appendix 2 (Tables A2.7 – A2.9).

91

Table 10. Means and SDs for %Transition of Diphthong and Hiatus, by Sequence Type,

Rate and V

Rate 1 Rate 2

Sequence Type Vowel Mean SD Mean SD

Diphthong

[a] 44.24 10.72 49.59 12.18

[e] 48.22 14.37 53.14 18.67

[o] 51.58 12.41 59.83 18.80

Hiatus

[a] 33.95 6.81 36.67 6.81

[e] 32.07 10.08 33.50 8.73

[o] 36.85 8.82 35.98 7.34

Similar to what we observed on the measure of normalized sequence duration, the group results

for %Transition (Figure 11 and Table 10)37

suggest a different pattern of V effects for

diphthongs and hiatuses. For diphthongs, we observe that, as predicted, sequences with [a] have

a shorter %Transition than diphthongs with [e] or [o], especially at Rate 1. At Rate 2, the

difference between [a] and [e] appears smaller while the difference between [a] and [o] remains.

For hiatuses, very little difference is observed in %Transition between sequences with [a] and

those with [o] at either speech rate.

%Tra

nsit

ion

V [o][e][a]

100

75

50

25

0[o][e][a]

Rate = 1 Rate = 2

Sequence Type

Diphthong

Hiatus


Figure 11. Bar chart of mean % transition by Sequence Type, Speech Rate and V

37 Refer also to Appendix 2 (Tables A2.7 – A2.9).

92

A repeated-measures ANOVA finds significant main effects of Sequence Type and V as well as

a significant Sequence Type*V interaction. Rate, however, once again is not significant.


Speech Rate and V


Main effects

Sequence Type F(1,18)=134.08 0.000

Rate F(1,18)=0.38 0.551

V F(2,18)=6.09 0.010

Interactions

Rate*Sequence Type F(1,18)=0.27 0.617

Rate*V F(2,18)=0.56 0.579

Sequence Type*V F(2,18)=5.76 0.012

Rate*Sequence Type*V F(2,18)=0.69 0.515


Post-hoc comparisons (Bonferroni) in Table 12 show that the significant V effect is largely due

to the effect of V on %Transition in diphthongs only. For Hiatus, the quality of V does not have

an effect on %Transition. Therefore, no significant differences exist in the data between hiatuses

with [a] and those with either [e] or [o]. For the Diphthong category, on the other hand,

sequences with [a] have significantly smaller %Transition than those with [o]. However, contrary

to our observations and predictions, diphthongs with [a] do not differ significantly from

diphthongs with [e] while diphthongs with [e] and [o] also differ significantly. Importantly, as

with the normalized duration measurements, we also note that the degree of difference between

Diphthong and Hiatus varies according to V. Here too, the difference between Diphthong and

Hiatus is smallest for sequences with [a], where the mean difference in %Transition is 9.63%

(averaged across both speech rates since no significant rate difference was found). For sequences

with [e], the mean difference in %Transition between Diphthong and Hiatus is 14.88% and for

sequences with [o] it is 15.41%. Thus, diphthongs and hiatuses with [a] are closer in %Transition

than their counterparts with [e] or [o].

93


%Transition, by Speech Rate and V

Vowel vs. t-value p

V

[a] [e] 0.04 1.000

[a] [o] 4.64 0.001

[e] [o] 4.60 0.001

Sequence Type*V

[a] [e] 2.12 0.724

Diphthong [a] [o] 5.66 0.000

[e] [o] 3.54 0.035

[a] [e] -2.06 0.806

Hiatus [a] [o] 0.90 1.000

[e] [o] 2.96 0.125

On the basis of the above results, we can propose the following hierarchies of %Transition

according to Sequence Type, Speech Rate and V:

(i) Diphthong (Rate 1 & Rate 2): [a],[e]<[o]

(ii) Hiatus (Rate 1 & Rate 2): [a]=[e]=[o]

Thus, as with sequence duration, diphthongs appear slightly more variable (i.e. more susceptible

to V effects) than hiatuses.

In the individual data (Figure 12; Appendix 2, Tables A2.6-A2.9), most speakers mirror the

global results and we find no significant Speaker effect. That is, the speakers generally have a

larger %Transition for diphthongs with [o] than for those with [a] or [e]. For hiatuses, on the

other hand, most speakers showed the expected consistency across vowels. One exception is

MM, who had a comparatively large %Transition for her [o] hiatuses at Rate 1 (53.46%),

perhaps indicative of a diphthongized pronunciation of ríos. Similarly, at Rate 1, CG has a larger

%Transition for [e] hiatuses (46.44%) than for her [e] diphthongs (41.04%).

94

%Tra

nsit

ion

100

50

0

100

50

0[o][e][a] [o][e][a]

V [o][e][a]

100

50

0[o][e][a]

A A A M A N C G

DH KR LG LL

MM MV

Sequence Ty pe

Diphthong

Hiatus

Rate = 1

%Tra

nsit

ion

100

50

0

100

50

0[o][e][a] [o][e][a]

V [o][e][a]

100

50

0[o][e][a]

A A A M A N C G

DH KR LG LL

MM MV

Sequence Ty pe

Diphthong

Hiatus

Rate = 2

Figure 12. Bar chart of mean %Transition for Sequence Type, V and Speaker:

Rate 1 and Rate 2

3.3 Frequency

Frequency contours for vocalic sequences are expected to differ according to whether the non-

high vowel (V) in the sequence is [a], [e] or [o]. For this reason, it is the within-vowel

comparisons of Sequence Type (Diphthong vs. Hiatus) which are of most interest in this section.

That is, in the analyses that follow, the Sequence Type*V are most important. For all analyses,

repeated-measures ANOVAs were carried out at each time point (1-10), for both F1 and F2 (in

Bark, as specified in §2.4.2).

3.3.1 Diphthong (já, jé, jó) vs. Hiatus (í.a ,í.e, í.o)

At the beginning of the chapter, we predicted that, for all levels of V, hiatuses would have more

peripheral F1-F2 values (lower F1 and higher F2) than diphthongs. Based on the results on the

temporal measurements, we also explore whether the differences in F1 and F2 between

Diphthong and Hiatus will turn out to be less extreme for sequences with [a] than for sequences

with [e] or [o]. As shown in Figure 13, the F1-F2 formant changes from onset to offset of the

95

sequences seem to contradict these predictions (except for the onset frequencies of sequences

with [o]).

F1(Bark)

F2 (

Ba

rk)

16

12

8

48642

8642

16

12

8

4

V = [a] V = [e]

V = [o]

Sequence Type

Diphthong

Hiatus

onset

offset

onset

offset

onset

offset

Figure 13. Scatterplot of F1-F2 formant changes from sequence onset to offset, by Sequence

Type and V

However, the above changes reveal nothing about differences between Diphthong and Hiatus at

other points within the formant contours of the sequences. If any such differences exist they may

be found in the time-normalized F1-F2 contours used in the present dissertation (refer to Figure

2, §2.4.1).

The results of the repeated-measures ANOVAs carried out for factors Sequence Type

(Diphthong vs. Hiatus), Rate (1 vs. 2) and V ([a] vs. [e] vs. [o]) are reported in Table 13, where

all significant p-values are shaded gray. Any interactions between these factors which did not

have consistently significant p-values were left out for the sake of clarity of presentation. This

includes the following interactions: Rate* Sequence Type, Rate*V and Rate*Sequence Type*V.

We immediately notice is that there are no consistent significant Rate effects for either F1 or F2.

On the other hand, there are significant Sequence Type*V interactions for both F1 and F2 at

almost every time point.

96

Table 13. ANOVA results for differences between Diphthong and Hiatus in F1 and F2, by

Speech Rate and V

Rate Sequence Type V Sequence Type*V

Frequency Time F(1,18) p F(1,18) p F(2,18) p F(2,18) p

F1

1 0.71 0.422 10.04 0.011 1.52 0.246 13.61 0.000

2 1.13 0.315 2.08 0.183 0.00 0.996 15.85 0.000

3 1.41 0.266 10.50 0.010 2.41 0.119 33.66 0.000

4 0.15 0.708 21.28 0.001 16.16 0.000 44.23 0.000

5 0.15 0.709 41.67 0.000 59.28 0.000 61.81 0.000

6 1.14 0.314 47.79 0.000 133.39 0.000 47.65 0.000

7 7.76 0.021 23.70 0.001 137.29 0.000 17.40 0.000

8 9.33 0.014 5.06 0.051 127.39 0.000 12.23 0.000

9 5.55 0.043 0.25 0.631 97.14 0.000 12.03 0.000

10 3.83 0.082 0.01 0.927 55.43 0.000 4.34 0.029

F2

1 0.41 0.537 1.73 0.221 41.77 0.000 3.59 0.049

2 1.20 0.302 11.06 0.009 31.07 0.000 7.95 0.003

3 6.29 0.033 44.64 0.000 32.45 0.000 14.91 0.001

4 5.81 0.039 99.59 0.000 55.34 0.000 18.08 0.000

5 1.81 0.211 117.32 0.000 101.68 0.000 19.94 0.000

6 0.34 0.576 75.93 0.000 169.87 0.000 13.55 0.000

7 0.01 0.910 33.62 0.000 193.08 0.000 7.74 0.004

8 0.88 0.372 15.64 0.003 207.54 0.000 2.13 0.148

9 1.41 0.265 0.24 0.633 98.86 0.000 2.45 0.115

10 0.04 0.846 4.69 0.059 13.57 0.000 8.09 0.003

The post-hoc (Bonferroni) comparisons in Table 14 show that, contrary to our predictions, there

are more significant differences between Diphthong and Hiatus in sequences with [a] than in

sequences with either [e] or [o]. In fact, the differences between [já] and [í.a] are found

throughout both F1-F2 contours, except at the very beginning and very end of the sequence.

While significant differences between [jó] and [í.o] occur in the middle of both the F1 and F2

contours, they are most obvious for F2. Fewer significant differences are apparent between [jé]

and [í.e] and these occur mainly in the middle portions (i.e. the transitions) of the F1 and F2

contours.

97

Table 14. Bonferroni post-hoc comparisons of differences in F1 and F2 between Diphthong

and Hiatus, by V

F1 F2

V Time T-Value P-Value T-Value P-Value

[a]

1 -1.13 1.000 2.08 0.607

2 -5.73 0.000 3.58 0.008

3 -8.98 0.000 5.37 0.000

4 -12.35 0.000 7.25 0.000

5 -16.88 0.000 8.47 0.000

6 -16.95 0.000 8.60 0.000

7 -11.27 0.000 6.94 0.000

8 -6.67 0.000 4.65 0.000

9 -3.56 0.009 1.14 1.000

10 -1.14 1.000 1.48 1.000

[e]

1 3.92 0.002 -0.77 1.000

2 0.35 1.000 0.39 1.000

3 -1.93 0.842 2.03 0.677

4 -3.96 0.002 3.13 0.034

5 -4.65 0.000 3.76 0.004

6 -5.15 0.000 4.04 0.002

7 -3.55 0.009 3.05 0.045

8 -0.28 1.000 1.56 1.000

9 2.19 0.459 -0.69 1.000

10 1.82 1.000 -0.98 1.000

[o]

1 5.91 0.000 1.53 1.000

2 0.33 1.000 4.45 0.000

3 -2.63 0.147 8.27 0.000

4 -3.85 0.003 11.39 0.000

5 -3.92 0.003 12.94 0.000

6 -3.55 0.009 11.83 0.000

7 -2.68 0.131 7.27 0.000

8 -1.05 1.000 3.65 0.006

9 -0.39 1.000 0.31 1.000

10 -1.01 1.000 0.32 1.000

In the following sections, we examine in greater detail the differences between Diphthong and

Hiatus that are found with each level of V.

3.3.1.1 Sequences with [a]

In essence, the values (both for F1 and F2) for [í.a] (Hiatus) are more peripheral while those for

[já] (Diphthong) are more centralized (Figure 14). That is, for [í.a] the values for F1 are lower

98

and the values for F2 are higher compared to [já]. Because the onset and offset F1 and F2 values

are similar for [í.a] and [já], the differences in the middle portion of their F1-F2 trajectories result

in a smoother slope for [já] and a steeper slope for [í.a].

Time

Fre

qu

en

cy

(B

ark

)

10987654321

15

10

5

V=[a]

Figure 14. Scatterplot of F1-F2 of Sequence Type, for V = [a]

In the individual data (Figure 15) we find that most of the speakers have a visible difference

between Diphthong and Hiatus in both the F1 and F2 contours. One exception is LG who shows

some overlap in the F2 contours. Speaker AA, on the other hand, stands out as having the most

noticeable difference between Diphthong and Hiatus in both F1 and F2.

99

Time

Fre

qu

en

cy

(B

ark

)15

10

5

15

10

5

10987654321 10987654321

10987654321

15

10

5

10987654321

A A A M A N C G

DH KR LG LL

MM MV

V=[a]

Figure 15. Scatterplot of F1-F2 of Sequence Type, for V = [a] by Speaker

3.3.1.2 Sequences with [e]

Although fewer points of difference were found between [jé] and [í.e], we still observe that,

where these differences occur, values for [í.e] are generally more peripheral than those for [jé],

just as we found for sequences with [a]. This pattern is most obvious in the middle portions of

the F1 and F2 contours, as is evident in the mean frequency values for the group (Figure 16). The

figure also highlights that relatively little movement occurs in the F1-F2 contours, especially for

Diphthong sequences [jé]. These fairly level contours are observed also in the individual data

(Figure 17) where we also note that most speakers have some overlapping values for Diphthong

and Hiatus, especially for F2. For F1, MM maintains the most obvious difference between

Diphthong and Hiatus throughout most of the contour.

100

Time

Fre

qu

en

cy

(B

ark

)

10987654321

15

10

5

V=[e]

Figure 16. Scatterplot of F1-F2 of Sequence Type, for V = [e]

Time

Fre

qu

en

cy

(B

ark

)

15

10

5

15

10

5

10987654321 10987654321

10987654321

15

10

5

10987654321

A A A M A N C G

DH KR LG LL

MM MV

V=[e]

Figure 17. Scatterplot of F1-F2 of Sequence Type, for V = [e] by Speaker

101

3.3.1.3 Sequences with [o]

Again, the values for [í.o] are, for the most part, more peripheral than those for [jó] (Figure 18).

Because the onset and offset F1 and F2 values for [í.o] and [jó] are not significantly different,

this results in a steeper slope for [í.o] (i.e. hiatus). This pattern is most obvious for the F2

contour. It is also evident in the individual data (Figure 19) where some speakers have visible

overlap of Diphthong and Hiatus values for F1. The least overlap is found consistently for F2,

although speakers AN and LG show more overlap than all the others. Speaker AA once again

presents the most noticeable difference between Diphthong and Hiatus in both F1 and F2, just as

she did for [já] and [í.a].

Time

Fre

qu

en

cy

(B

ark

)

10987654321

15

10

5

V=[o]

Figure 18. Scatterplot of F1-F3 of Sequence Type, for V = [o]

102

Time

Fre

qu

en

cy

(B

ark

)15

10

5

15

10

5

10987654321 10987654321

10987654321

15

10

5

10987654321

A A A M A N C G

DH KR LG LL

MM MV

V=[o]

Figure 19. Scatterplot of F1-F2 of Sequence Type, for V = [o] by Speaker

3.4 Discriminant Analysis

We now turn to the question of whether this variety of Spanish has instances of ambiguous

sequences. We are mainly looking for cases of diphthongs produced as hiatuses (i.e. exceptional

hiatuses) but hiatuses produced as diphthongs are also possible. Here, we use Discriminant

Analysis (DA) to decide category membership based on the acoustic predictors tested (refer to

§2.4.3 for an explanation of the technique). To recap, these predictors are: normalized sequence

duration, proportion of sequence taken up by the transition, and time-normalized F1-F2

measurements.

3.4.1 Data Preparation and Procedures

Prior to applying the Discriminant Analysis procedure, however, the total number of predictors

needed to be reduced. Specifically, using all the F1-F2 formant measurements as predictors

created a situation with a very large number of predictors (2 formants X 10 time points = 20

frequency predictors). In addition, many of these measurements are correlated since none of the

10 measurements made along the F1 and F2 contours is entirely independent of the previous or

following measurement (McDougall, 2006). Thus, in an effort to reduce the number of predictors

103

used in DA, regression was used to fit the F1 and F2 contours of the sequences with polynomial

equations. This technique has proved useful in capturing individual differences in diphthong

production (McDougall, 2006, for Australian English). This technique has also been used by

Aguilar (1997, 1999) to capture the differences between the curvatures in the F1–F2 contours of

Peninsular Spanish diphthongs and hiatuses. In Aguilar (1997, 1999) the data for all non-high

vowels was combined to obtain the equation and a quadratic polynomial was found to provide

the best fit. In the present study, because different vowels had different results for frequential

parameters (§3.3) the polynomial equations for each non-high V were obtained separately. For

all three non-high vowels (a, e, and o) the best fit for the F1 contours of both diphthongs and

hiatuses was a cubic polynomial of the form: y= x0+ x1t+ x2t2+ x3t

3. In the equation, t represents

normalized time (i.e. each of the 10 frequency measurement points), the constant term (x0)

represents the value of the y intercept, and the coefficients (x1, x2, x3) represent the slope, shape

and direction of the formant curve. For the F2 contours, the best fit for [a] and [o] sequences

(both Diphthong and Hiatus) and for [e] (Hiatus only) was also a cubic polynomial. For [e]

Diphthong sequences, on the other hand, a quadratic polynomial (y= x0+ x1t+ x2t2) provided the

best fit for the F2 contour. This is in line with the observation made in §3.3.1.2 that the F2

contours of sequences with [e] show relatively little movement. The equations for the diphthong

and hiatus sequences are given in Table 15.

Table 15. Mean values of the polynomial equation constants and coefficients of F1 and F2

for Diphthong and Hiatus, by V

F1 F2

Sequence x0 x1 x2 x3 R-Sq(Adj) x0 x1 x2 x3 R-Sq(Adj)

[í.a] 4.74 -1.00 0.25 -0.01 97.9% 13.46 0.79 -0.16 0.01 98.5%

[já] 4.15 -0.43 0.21 -0.01 99.7% 13.52 0.55 -0.15 0.01 99.9%

[í.e] 4.61 -0.65 0.15 -0.01 92.6% 13.63 0.19 0.02 -0.01 99.1%

[jé] 4.10 -0.33 0.12 -0.01 98.6% 13.71 0.24 -0.03 N/A 99.1%

[í.o] 4.58 -0.66 0.17 -0.01 97.1% 12.28 1.38 -0.30 0.01 98.7%

[jó] 3.85 -0.14 0.08 -0.01 99.3% 12.80 0.73 -0.23 0.01 99.8%

In order to reduce even further the number of predictors used in the Discriminant Analysis,

Repeated Measures ANOVAs (with factor Sequence Type) were carried out on the above

equations. Each non-high V was tested separately and the results of these tests are given in Table

16. They reveal that there are indeed significant differences between Diphthong and Hiatus in the

equation constant term (x0) alone or in combination with one or more of its coefficients (x1, x2,

and x3). These results, on the surface, appear to confirm the findings of the raw frequential data

104

(Tables 13 and 14). At the same time, however, these results contradict what we observed in the

raw data. Specifically, we observe that, contrary to what we found with the raw frequency data,

fewer significant points of difference exist between Diphthong and Hiatus where V is [a]. For

F1, for example, Diphthong and Hiatus sequences with [a] differ significantly in both intercept

(x0) and slope (x1), with Hiatus sequences starting at a higher frequency and having a steeper

slope. For F2, Diphthong and Hiatus sequences with [a] differ only in the magnitude of the slope.

Sequences with [e] and [o], on the other hand, have more significant points of difference. Thus,

once again (just as we saw for normalized duration and % transition), we find fewer differences

between Diphthong and Hiatus when V is [a].

Table 16. ANOVA table for differences between Diphthong and Hiatus in the polynomial

constants and coefficients of F1 and F2 trajectories

F1 F2

V Coefficient F(1,9) p F(1,9) p

[a]

x0 21.09 0.001 0.49 0.503

x1 12.08 0.007 9.37 0.014

x2 1.05 0.332 0.31 0.590

x3 0.44 0.522 0.44 0.523

[e]

x0 28.29 0.000 13.86 0.005

x1 9.57 0.013 31.35 0.000

x2 1.54 0.246 25.94 0.001

x3 0.10 0.756 N/A N/A

[o]

x0 68.59 0.000 8.96 0.015

x1 37.18 0.000 84.50 0.000

x2 18.27 0.002 11.18 0.009

x3 10.29 0.011 0.13 0.730

These results suggest that the time-normalized raw frequential measurements may be capturing

some non-essential information about the sequences in question (McDougall, 2006, p.102).

While these raw measurements may prove useful in highlighting the differences in the general

shape of the F1-F2 contours between Diphthong and Hiatus, the polynomial equations may

provide a more meaningful summary of the frequential data. Thus, the equations can be used to

illustrate the most significant aspects of the frequency contours. We therefore proceeded to use

them as predictors in the Discriminant Analysis (DA). Once the appropriate polynomial for each

V was established, polynomial fittings were performed on each token, using MATLAB

(MathWorks, 2007). The results were then evaluated in the Discriminant Analysis procedure.

105

3.4.2 Discriminant Analysis Results

While the temporal measurements (normalized duration and %Transition) were significant for all

non-high vowels, the significant frequency predictors differed for each V (Table 17). For this

reason, we examine the results for each non-high V separately.

Table 17. Significant predictors for inclusion in discriminant analysis, by V (acoustics)

Non-high vowel

Predictors [a] [e] [o]

F1x0

F1x1

F1x2

F1x3

F2x0

F2x1

F2x2

F2 x3 Normalized duration

%Transition

TOTAL 5 7 9


Where V= [a], there are five possible predictors: F1x0, F1x1, F2x1, normalized sequence duration,

and %Transition. When all the token files for Diphthong and Hiatus and all five significant

predictors are included in the analysis, we find that approximately 77% of diphthongs and 82%

of hiatuses were classified according to their expected production. Overall, almost 78% of

sequences were correctly classified.

Table 18. Discriminant analysis summary table for V= [a] (acoustics)

TRUE GROUP Squared distance between groups

Put into group Diphthong Hiatus Diphthong Hiatus

Diphthong 276 22 0.000 2.701

Hiatus 84 98 2.701 0.000

Total N 360 120 F (5, 474) = 48.22, p=0.01

N Correct 276 98

Proportion Correct 0.767 0.817

TOTALS N=480(0 missing values) N Correct=374 Proportion Correct= 0.779

106


Where V= [e], the total number of possible predictors increases to seven. Including all of them

produces an overall correct classification rate of about 85%. Both Diphthong and Hiatus had

correct classification rates of over 80% with hiatuses having a slight advantage (at 90%) over

diphthongs (at 84%).

Table 19. Discriminant analysis summary table for V= [e] (acoustics)



Diphthong 338 6 0.000 3.984

Hiatus 65 54 3.984 0.000

Total N 403 60 F (5, 457) = 41.52, p=0.01

N Correct 338 54


TOTALS N= 463(17 missing values) N Correct= 392 Proportion Correct= 0.847


The total number of possible predictors is highest when V= [o]. Including all these predictors

gives the best correct classification rate of all the levels of V, at over 95%. In contrast to what we

saw with [a] and [e], however, hiatuses (at 97% correct) did not have an appreciable advantage

over diphthongs (96%).

Table 20. Discriminant analysis summary table for V= [o] (acoustics)



Diphthong 171 2 0.000 14.214

Hiatus 8 58 14.214 0.000

Total N 179 60 F (5, 233) = 68.58, p=0.01

N Correct 171 58


TOTALS N= (239, 1 missing values) N Correct= 229 Proportion Correct= 0.958

In summary, we note that the squared distances between groups were significant for all three

levels of V. Thus, we can assume that the chosen predictors are successfully discriminating

between Diphthong and Hiatus categories. However, we also find that sequences with [a] have

lower correct classification rates and a smaller squared distance between groups than sequences

with [e] or [o]. Sequences with [o] have the best correct classification rates. Finally, we note that,

while for all three levels of V diphthongs have slightly worse classification rates than hiatuses,

107

the difference in correct classification rate between Diphthong and Hiatus is greatest for

sequences with [a].

We now turn to the question of what words are most likely to be misclassified as well as which

Speakers are most likely to produce misclassified words.

3.4.3 Misclassified Sequences

Because in the Discriminant Analysis some instances of misclassification are due to tokens

whose measurements fall close to the mean for both Diphthong and Hiatus, it’s not enough to

consider the predicted group membership. It is also important to look at the probability of falling

within the predicted group. Arbitrarily, we have divided these probabilities into three groups, the

first of which (50-59%) may be considered to contain marginal cases and the last (70% or

greater) may be considered to contain the most clear-cut cases.


The expectation for these sequences was that they would have the highest number of

misclassified cases. In particular, we expected the diphthongs with [a] to be most consistently

classified as hiatuses since they meet the established criteria for words commonly identified as

exceptional hiatuses (e.g. Hualde, 2005). The first criterion is that they all have [a] as the non-

high vowel (Hualde 2005). Second, they appear in stressed syllables (Chitoran & Hualde, 2007).

Also, some of the words have related words with hiatus (Cabré & Prieto, 2006). Finally, they are

derived from Latin heterosyllabic [iV] sequences (Chitoran & Hualde, 2007; Colantoni &

Limanni, 2010). The results in Table 21 illustrate that this expectation was clearly met. In the

Diphthong category, the words with the most misclassifications were, in descending order,

diario, diablo and criada. In the Hiatus category, crías had the highest number of

misclassifications.

108

Table 21. Summary of discriminant analysis classification (predicted group membership)

of Diphthong and Hiatus: V= [a] (acoustics)

Expected group Word

Predicted Group Probability

Diphthong Hiatus 50%-59% 60%-69% 70%+

Diphthong

criada 42 18 5 3 10

diablo 39 21 5 3 13

diario 29 31 5 7 19

piada 51 9 4 2 3

piano 58 2 1 1 0

viaje 57 3 1 2 0

Hiatus crías 15 45 4 5 6

días 7 53 2 0 5

The misclassified cases point to considerable between-speaker variation (Table 22). For

example, AM had the highest number of misclassified Diphthong with [a] (14) followed by MV

(12) and MM (11). These speakers, however, differ on the number of misclassified Hiatus they

contribute. Speakers MV and MM also contribute the highest number of misclassified Hiatus (9

cases and 6 cases, respectively) while AM contributes only 2 cases. At the other end of the

spectrum is KR, with no misclassifications at all, either for Diphthong or Hiatus. The remaining

speakers contribute an intermediate number of misclassified Diphthong cases (between 6 and 10)

and few misclassified Hiatus cases (between 0 and 2).

Table 22. Summary of misclassified sequences with [a], by Speaker (acoustics)

SPEAKER

Expected group Word AA AM AN CG DH KR LG LL MM MV

Diphthong

criada 2 2 4 3 0 0 1 3 1 2

diablo 1 6 1 0 2 0 0 1 6 4

diario 3 3 2 5 5 0 4 3 3 3

piada 1 0 1 0 0 0 0 3 1 3

piano 0 1 0 1 0 0 0 0 0 0

viaje 0 2 0 0 0 0 1 0 0 0

Hiatus crías 2 1 1 1 0 0 0 1 5 4

días 0 1 0 0 0 0 0 0 1 5

TOTAL 9 16 9 10 7 0 6 11 17 21


The expectation for diphthongs with [e] was that the word bienio would be most consistently

misclassified as hiatus because of its bimorphemic structure (e.g. Chitoran & Hualde, 2007;

Cabré & Prieto, 2006) and its relative infrequency (e.g. Whitley, 1985). We also expected bienio

109

to contrast with bienes which is a more common word and its diphthong is derived from breaking

of the Latin short mid vowel Ĕ (Chitoran & Hualde, 2007). Thus, bienes should be consistently

identified correctly. The data in Table 23 show that, in fact, bienio is the word with the most

misclassifications: almost 50% of the bienio tokens are misclassified as hiatus (with most of

these at over 70% probability). With bienes, the number is much lower at approximately 15%,

but this number is hardly insignificant. In fact, it is higher than the number for cliente (with

approximately an 8% misclassification rate), a word which is derived from a Latin heterosyllabic

[iV] sequence and should thus have stronger hiatic tendencies. The fewest misclassified cases

occur for pieza (with no misclassifications) and viejo, (with a single misclassification). Finally,

prieto (at 20%) and pliegue (at 17%) had similar misclassification rates as bienes, despite the fact

that they, too, are derived from Latin Ĕ.


of Diphthong and Hiatus: V= [e] (acoustics)

Expected group Word



Diphthong

bienes 51 9 4 0 5

bienio 29 28 3 3 22

cliente 55 5 3 1 1

pieza 59 0 0 0 0

pliegue 47 12 7 1 4

prieto 50 10 2 6 2

viejo 47 1 0 1 0

Hiatus ríen 6 54 3 2 1

Similar to what we observed for sequences with [a], we find considerable between-speaker

variation for sequences with [e] (Table 24). Speaker AM had the highest number of misclassified

diphthongs with [e] (18) followed by KR (15). These results highlight the degree of within-

speaker variation in response to vowel context for these sequences. For instance, AM also had

the highest number of misclassified Diphthong with [a], thus her behaviour appears consistent

across vowel contexts. Other speakers were equally consistent: speakers AA, AN, LL and LG

had comparable numbers of misclassified diphthongs for [a] and [e]. On the other hand, KR had

no misclassified diphthongs for [a] while for [e] she contributes many more misclassified

sequences. Other speakers also behaved differently according to vowel context. For example,

Speakers MM, MV, DH and CG all had fewer misclassified sequences with [e]. Speakers who

had misclassified Hiatus sequences with [a] generally had fewer misclassified Hiatus sequences

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with [e]. Surprisingly, Speaker DH had no misclassified cases of ríen, even though she was

previously identified (§3.1.1) as producing very short hiatuses with [e].

Table 24. Summary of misclassified sequences with [e], by Speaker (acoustics)

SPEAKER


Diphthong

bienes 1 6 0 0 0 0 0 2 0 0

bienio 6 6 5 2 0 6 0 1 0 2

cliente 1 2 0 0 0 1 0 1 0 0

pieza 0 0 0 0 0 0 0 0 0 0

pliegue 0 2 3 1 0 3 1 2 0 0

prieto 0 1 0 1 0 5 2 1 0 0

viejo 0 1 0 0 0 0 0 0 0 0

Hiatus ríen 0 0 0 0 0 0 2 0 2 2

TOTAL 8 18 8 4 0 15 5 7 2 4


For diphthongs with [o] the words criollo and piojo have been identified as candidates for

exceptional hiatus in Peninsular (Castillian) Spanish (Hualde, 2005, p. 85, Table 5-10) based on

their etymologies. For example, criollo is a loanword from the Portuguese crioulo (with a

heterosyllabic vowel sequence). The diphthong in piojo, on the other hand, originates from a

VCV sequence in the Latin word PEDUCULUS (via deletion of intervocalic C along with other

consonant and vowel change processes). The data in Table 25, however, only partially confirm

these expectations. The word criollo behaves as predicted with approximately 8.5% of cases

misclassified as hiatus, with most of these at over 70% probability. For piojo however, the

expectation was not met. In fact, no cases of piojo were misclassified as hiatus.


of Diphthong and Hiatus: V= [o] (acoustics)

Expected group Word



Diphthong

criollo 54 5 0 1 4

piojo 60 0 0 0 0

viola 57 3 2 0 1

Hiatus ríos 2 58 0 0 2

Overall, speakers had very few misclassified sequences with [o], regardless of whether they had

few or many misclassified sequences with the other vowels (Table 26). Speaker LG contributed

the highest number of misclassified diphthongs (3). Only 2 cases of misclassified Hiatus were

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found and both were produced by speaker MV. This result is in line with our observation

(§3.1.1) that her comparatively short [o] hiatuses were indicative of a diphthongized production

of ríos.

Table 26. Summary of misclassified sequences with [o], by Speaker (acoustics)

SPEAKER


Diphthong

criollo 0 1 0 1 0 0 2 0 0 1

piojo 0 0 0 0 0 0 0 0 0 0

viola 0 1 0 0 1 0 1 0 0 0

Hiatus ríos 0 0 0 0 0 0 0 0 0 2

TOTAL 0 2 0 1 1 0 3 0 0 3

4 Summary and Discussion

In this section we summarize the findings of the study, evaluate whether the study hypotheses are

confirmed by the data, and discuss the results in light of previous studies.

4.1 Hypothesis 1: Diphthong vs. Hiatus

Hypothesis 1 stated that diphthongs and hiatuses in Mexican Spanish differ according to certain

acoustic parameters. This hypothesis is confirmed. Thus, we find that category membership of

Diphthong and Hiatus is defined by sequence duration, proportion of sequence dedicated to

transition, and the overall shape of the F1-F2 contours. Furthermore, these category differences

between Diphthong and Hiatus are retained under different speech rate conditions. The last two

measures, in fact, appear immune to speech rate effects. For example, although both Diphthong

and Hiatus experience a decrease in duration as speech rate increases, Diphthong is always

shorter than Hiatus. In terms of %Transition, diphthongs are shorter than hiatuses but have

greater %Transition. Thus, we find a negative relationship between sequence duration and

%Transition. Unlike sequence duration, however, %Transition appears resistant to speech rate

changes in our data sample. That is, even though we found that sequence duration decreases as

speech rate increases, we do not find a corresponding increase in %Transition. With regard to

frequency patterns, the overall pattern is that diphthongs generally have a smoother, more

gradual slope in F1-F2 and more centralized values, while hiatuses have a sharper slope and

more peripheral values. Rate increase once again appears not to have any effect on this last

parameter and F1-F2 contours for both Diphthong and Hiatus remain similar across speech rates.

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Many of these global differences in duration, %Transition and F1-F2 contours between

Diphthong and Hiatus appear in different degrees according to the identity of the V portion of the

sequence. We discuss these differences among levels of V with more detail below in the

evaluation of Hypothesis 2.

4.2 Hypothesis 2: Vowel Effects

Hypothesis 2 predicted that the quality of the non-high vowel (V) in both Diphthong and Hiatus

sequences would produce acoustic consequences. The specific prediction was that sequences

where V= [a] would have more extreme values on both the temporal and frequential measures.

This hypothesis was also largely confirmed. We find, for example, that at the slower speech rate

(Rate 1) both diphthongs and hiatuses with [a] are longer than those with either [e] or [o].

However, with an increase in speech rate (Rate 2), the pattern was maintained only for

diphthongs. For hiatuses, there were no significant differences in duration attributable to V at

Rate 2. More importantly, however, we find that Diphthong and Hiatus sequences with [a]

(although longer overall) are closer to each other in duration than their counterparts with either

[e] or [o].

As regards %Transition, we find that vowel quality has an effect on diphthongs but not on

hiatuses. Therefore, we find no significant differences between hiatuses with [a] and those with

[e] or [o]. On the other hand, diphthongs with [a] have a significantly smaller %Transition than

those with [o] but do not differ from those with [e]. Most important, however, is the finding that

the degree of differences between Diphthong and Hiatus also varies according to V. Specifically,

the difference between Diphthong and Hiatus in %Transition is smallest for sequences with [a].

Thus, we find that between Diphthong and Hiatus sequences with [a] are closer to each other in

%Transition than their counterparts with either [e] or [o]. This is the same pattern we observed

for sequence duration.

With reference to frequential measurements, the information found in the time-normalized F1-F2

contours suggested that diphthongs and hiatuses with [a] were further apart than those with either

[e] or [o]. That is, there were more significant points of difference between Diphthong and

Hiatus with [a]. However, a different picture emerged when we converted the contours to

polynomial equations and submitted these to statistical analysis. After eliminating some of the

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redundant information in the time-normalized raw frequential measurements, we found, that

there were, in fact, fewer differences between Diphthong and Hiatus in sequences with [a].

Overall then, on all three measures, we find that Diphthong and Hiatus sequences with [a] are

closer to each other than their counterparts with either [e] or [o]. This outcome may help explain

the observation that most instances of exceptional hiatuses occur with sequences where [a] is the

non-high vowel (e.g. Hualde, 2005). Thus, it is possible that the intrinsic phonetic properties of

sequences with [a] are behind the historic, prosodic and morphological triggers of exceptional

hiatus. In the evaluation of Hypothesis 3, below, we look at how these intrinsic differences

among levels of V combine with individual variation in the production of diphthongs and

hiatuses to produce sequences which do not fall neatly into either the Diphthong or Hiatus

category.

4.3 Hypothesis 3: Exceptional Hiatuses

Hypotheses 3 predicted that individual variation in the production of diphthongs and hiatuses

would (i) be reflected acoustically and (ii) give rise to sequences whose category membership is

ambiguous, as in the case of exceptional hiatuses.

The first part of the hypothesis was confirmed: we indeed found individual variation in the

production of diphthongs and hiatuses, with the variation appearing on one or more of the

parameters considered. On the measure of sequence duration (normalized), some speakers

produce larger differences between Diphthong and Hiatus. For sequences with [a], for example,

we find that Speakers MM and MV had small differences between Diphthong and Hiatus, due to

comparatively long [a] diphthongs, especially at Rate 1. Thus, we might expect them to produce

more exceptional hiatuses with [a] diphthongs than those speakers who had the largest

differences between Diphthong and Hiatus (i.e. AN, CG, DH and KR). As we saw in Table 22

(§3.4.3.1) this is indeed the case for these speakers. Speaker DH, on the other hand, has a small

difference between Diphthong and Hiatus for [e] sequences. In this case, the reason for the small

gap is that she produces relatively short hiatuses with [e] at both speech rates. However, in her

case, we fail to find any cases of diphthongized production of [í.e] sequences (Table 24,

§3.4.3.2). Speaker MV also had a small difference between Diphthong and Hiatus for her [o]

sequences at Rate 1, which results in a diphthongized production of [í.o] sequences (Table 26,

§3.4.3.3). The data for %Transition also points to variability in the amount of difference between

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Diphthong and Hiatus. On this measure, speakers AA, AM, AN, CG and LG have the smallest

Diphthong-Hiatus differences for sequences with [a] (for Rate 1 and/or Rate 2). For some of

these speakers the difference is due to a small %Transition for diphthongs (Speakers AA, AM

and AN). For others, the small difference between Diphthong and Hiatus is due to a large

%Transition for hiatuses (Speaker LG). For speaker CG, on the other hand, both diphthongs and

hiatuses (at Rate 2) had similar %Transition. CG also had small differences between Diphthong

and Hiatus for her [e] and [o] sequences, in this case due to a relatively large %Transition for

hiatuses. Speaker MM also had a small difference in %Transition between Diphthong and Hiatus

for her [o] sequences at Rate 1 due to a comparatively large %Transition for her [o] hiatuses.

However, this small difference did not result in a diphthongized production of any of her [í.o]

sequences (Table 26, §3.4.3.3). In terms of F1-F2 contours, Speaker AA stands out as having the

most noticeable difference between Diphthong and Hiatus in both F1 and F2 for sequences with

[a] and [o]. On the other hand, MM maintains the most noticeable difference in F1 for sequences

with [e].

The second part of the hypothesis was also confirmed as the speakers produced several

sequences whose category membership was not clear-cut. To test the second part of the

hypothesis, we used Discriminant Analysis to categorize sequences as Diphthong and Hiatus

according to the chosen temporal and frequential parameters. In the analysis, instances of Hiatus

misclassified as Diphthong were considered diphthongized while cases of Diphthong

misclassified as Hiatus were considered exceptional hiatuses. We observed that among the

speakers who contributed the most misclassified Diphthong cases where V= [a] were those who

were identified as having relatively small Diphthong-Hiatus differences on both normalized

duration and %Transition. This list includes MM, MV and AM. Conversely, speaker KR, who

produced larger differences between Diphthong and Hiatus on both measures, had no

misclassified cases of either Diphthong or Hiatus. However, some speakers who also had

relatively large differences between Diphthong and Hiatus on these measures (i.e. DH and LL)

also contributed several cases. Thus, for these speakers the small difference between Diphthong

and Hiatus may lie in the frequency contours. However, in Figure 15 (§3.3.1.1) it is not the case

that these speakers had more overlap in F1-F2 between Diphthong and Hiatus than other

speakers.

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We also find that while some speakers were consistent across different vowel contexts (i.e.

contributed similar number of misclassified sequences regardless of V), others were less

consistent. For example, Speaker AM contributed the highest number of misclassified

diphthongs for both [a] and [e]. On the other hand, speakers MM and MV, who also contributed

many misclassified sequences with [a], had very few cases with [e].

4.4 Discussion

On many points, the present results for Mexican Spanish vocalic sequences are in agreement

with the results for other dialects of Spanish and other languages. On the other hand, we do find

points of difference which suggest that some features of these sequences are language, dialect

and even sequence-specific. For example, we find that diphthongs are distinguished temporally

from hiatuses in that hiatuses are longer (Aguilar, 1999; Hualde & Prieto, 2002) and devote a

smaller proportion of the sequence to the transition (MacLeod, 2007). An increase in speech rate

tends to decrease the overall duration in all sequences such that the Diphthong- Hiatus contrast is

preserved across changes in speech rate (Aguilar, 1997, 1999). However, in our data an increase

in speech rate did not result in the expected increase in %Transition. Thus, %Transition appears

to be unaffected by speech rate in this variety of Spanish. Our results are in line with Peeters

(1991) who argues that the proportion of the sequence allotted to the transition is language-

specific. Our results also seem to support Ren (1986, p. 85), who suggests the transition from a

high glide ([j] in our case) to a low vowel (in our case a ‘lower’ vowel) is temporally insensitive

(i.e. remains constant across differences in speech rate). Similarly, we establish that durational

differences are affected by the identity of the V in the sequence, as observed by Aguilar (1997,

1999) and Lindau et al. (1990). However, our specific results are not necessarily the same as

those of other authors. For example, Aguilar (1999, p. 64) found that among Rising sequences

such as those used in the present experiment “hiatuses with [a] are longer than hiatuses with [e]

and [o], whereas for diphthongs, the behaviour is the opposite”. In the present study we also

observe a difference in the way the duration of diphthongs and hiatuses is affected by V. Our

results are different from Aguilar (1999) in that we find that diphthongs with [a] are longer than

diphthongs with either [e] or [o], regardless of speech rate. However, for hiatuses, these

durational differences occur only for Rate 1. Rate 2 hiatuses seem unaffected by the identity of

V. Some of these differences may be attributed to the variety of Spanish under study (Mexican

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Spanish here vs. Peninsular Spanish in Aguilar, 1999). However, the differences may also be the

result of using normalized duration (in the present study) instead of raw duration (Aguilar, 1999).

In terms of frequential differences between diphthongs and hiatuses, the overall pattern we

observe is that diphthongs generally have a smoother, more gradual slope in F1-F2 and more

centralized values, while hiatuses have a sharper slope and more peripheral values. This is in

agreement to the results of Aguilar (1997, 1999). We also found that the F1-F2 contours

remained largely invariant across different speech rates. This result is similar to what was

reported by Borzone de Manrique (1979, p. 202) for diphthongs in Argentine Spanish. She found

that the F2 rate of change for those sequences remained invariant across different speaking rates.

In terms of individual variation, we found that some speakers maintained a more extreme

difference between Diphthong and Hiatus on either the durational or frequential parameters or

both. This result is similar to what has already been observed by other authors (MacLeod, 2007;

Colantoni & Limanni, 2010) and also serves to underscore the view expressed in Docherty

(2003) that even speakers of the same language or variety may not behave in a linguistically

homogeneous manner due to their different experiences with the language. In addition to this

inter-speaker variation in diphthong and hiatus production, we also found considerable intra-

speaker variation related to the identity of the non-high vowel in the sequence. Some speakers,

for example, consistently maintained a similar acoustic distance between Diphthong and Hiatus

across vowel contexts. Others behaved differently according to the identity of the non-high V.

This intra-speaker variation was also reflected in the number of misclassified sequences each

speaker contributed for each V. The misclassified sequences, in particular those cases of

Diphthong classified as Hiatus, also serve to highlight that even those Spanish varieties not

normally associated with the production of exceptional hiatuses can show hiatic tendencies in the

production of some sequences. This finding is in line with Whitley (1985, reviewed in Chapter 2)

who also observed that the influence of dialect on the interpretation of [jV] sequences as [iV]

was unclear. Similar to what we observe in this study, Whitley (1985) found individual variation

was more consistent than dialectal variation with some speakers showing more or less of a hiatic

tendency than other speakers of the same dialect. In addition, Whitley (1985) suggests that the

words that trigger a hiatic pronunciation may differ from variety to variety as well as from

speaker to speaker. In our data, for example, the words prieto and pliegue were the most

consistently misclassified as exceptional hiatus among sequences where V= [e]. In addition, the

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word bienes also had several misclassified cases. This is unexpected since the diphthongs in all

these words are derived from breaking of the Latin short mid vowel Ĕ and, according to Chitoran

& Hualde (2007, p. 46), all such sequences are obligatorily realized as diphthongs. However,

other factors may be influencing the comparatively high misclassification rates for these words.

For example, the high misclassification rates for prieto may reflect both a language-specific

tendency for a preceding [r] to promote hiatus in Spanish (Hualde & Prieto, 2002) as well as a

more general cross-linguistic pattern of avoiding [j] after rhotics (Van der Beer, 2006; Hall &

Hamann, 2010). The high misclassification rate for pliegue, on the other hand may reflect the

well-documented instability of consonant+lateral clusters in Romance (e.g. Colantoni & Steele,

2005). In addition, in both prieto and pliegue the diphthong [jé] is preceded by a consonant

cluster. Thus, their misclassification rates may also be indicative of a more general tendency to

avoid diphthongs (i.e. a complex nucleus) after a complex onset. This tendency is documented

for other Romance languages including French (e.g. Chitoran & Hualde, 2007), Romanian

(Chitoran, 2002) and Catalán (Cabré & Prieto, 2004) as well as other varieties of Spanish (e.g.

Cabré & Prieto, 2006 for Peninsular Spanish). However, in this case we would also expect

cliente (especially since it is also derived from a Latin heterosyllabic sequence) to have a

comparable number of misclassified cases but it has fewer. Perhaps the explanation for the

unexpected misclassification rates for cliente and bienes is to be found in articulation. We return

to this question in Chapter 4 when we examine the articulatory characteristics of these vocalic

sequences.

Finally, we also find, like other authors (e.g Chitoran & Hualde, 2007; Hualde, 2005) that

diphthongs with [a] have the highest misclassification rate. Our study, however, emphasizes the

phonetic properties of diphthongs with [a] that might explain their hiatic tendency, rather than

their historical source alone. Recall that, on all three measures, we found a smaller degree of

difference between Diphthong and Hiatus in sequences with [a] than in sequences with either [e]

or [o]. This sequence-specific variability in diphthong and hiatus production is likely a reflection

the articulatory properties of the V ([a,e,o]) in the sequences. Specifically, the longer tongue/jaw

trajectories required for sequences with the low vowel [a] are likely responsible for longer

sequences overall as well as a smaller degree of difference between diphthongs and hiatuses with

[a]. This, in turn, results in more sequences with [a] being misclassified. In fact, when we

perform a Discriminant Analysis (using only those predictors identified as statistically

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significant) on the data for each V separately, we find that the mean squared distance between

groups is smallest for sequences with [a] (2.701), followed by sequences with [e] (3.984).

Sequences with [o] had the largest mean squared distance between Diphthong and Hiatus

(14.214). Consequently, it is not surprising that sequences with [a] had the lowest percentage of

correctly classified sequences (77.9%), followed by sequences with [e] (84.7%). Sequences with

[o] had the greatest percentage of correctly classified sequences (95.8%). With all three levels of

V, hiatuses had a slight advantage over diphthongs in terms of correct classification with the

advantage being greatest for sequences with [a].

5 Conclusions

In this chapter we have shown that Mexican Spanish diphthongs and hiatuses form separate

categories which can be distinguished acoustically along frequential and temporal parameters,

with the distinctions remaining stable across changes in speech rate. We have also shown that

there is evidence of blurring across the two categories such that, in some cases, diphthongs may

be misclassified as hiatus and vice versa. Importantly, this suggests that even Spanish varieties

(like Mexican Spanish) described as highly diphthongizing can produce exceptional hiatuses.

This finding supports the first research goal of this dissertation (as stated Chapter 1).

In addition, we have also identified sequence-specific and speaker-specific tendencies in both

the categorization of diphthongs and hiatuses and in the production of misclassified sequences.

We have attributed the sequence-specific variability to properties of the non-high vowel in the

sequences. We have found that the speaker-specific and sequence-specific tendencies can

intersect. That is, individual speakers may show either a pattern of consistency across vowel

contexts or a different pattern according to vowel context. We suggested at the beginning of the

chapter, in stating Hypothesis 3, that the speaker-specific characteristics of these sequences can

be attributed to distinctive patterns of articulation. In a similar vein, other authors have suggested

that vocalic sequences can be characterized with the same gestural coordination patterns as

sequences of consonants and vowels (Chitoran & Hualde, 2007). However, without data to

provide details of the articulatory parameters underlying these acoustic differences, these

proposals remain untested. Finally, we have not addressed whether a speaker’s production of

misclassified sequences is related to her perception of these sequences. That is, is a speaker who

produces many misclassified Diphthong tokens better able to identify cases of exceptional

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hiatuses? Related to this is the question of whether a sequence that is consistently misclassified

by a Discriminant Analysis procedure will be similarly subject to misclassification by listeners in

a perception experiment.

The next two chapters describe experiments which attempt to address the articulatory and

perception gaps in the characterization of these vocalic sequences. The relationship between

these sequence-specific and speaker-specific differences to different articulatory patterns and

strategies is examined in Chapter 4. The relationship between the present results and speakers’

perception of unambiguous and ambiguous sequences as either Diphthong or Hiatus is explored

in Chapter 5.

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Chapter 4 Articulatory Analysis of Vocalic Sequences in Mexican Spanish

1 Introduction

The present chapter reports an experiment which provides articulatory movement data on vocalic

sequences in Mexican Spanish. These sequences include glide-vowel (jV, diphthongs) and high

vowel-vowel (íV, hiatuses) sequences. The experiment was motivated by the desire to test

various claims regarding the articulatory characteristics of these sequences in Spanish. Some of

these claims emerged from the acoustic data analyzed in Chapter 3 of the present thesis; others

have their source in previous studies, both experimental and theoretical.

In the previous chapter, Chapter 3, we found both speaker-specific and sequence-specific

tendencies in the acoustic characterization of diphthongs (Diphthong) and hiatuses (Hiatus) in

Mexican Spanish. We suggested that these tendencies stem in part from speaker-specific and

sequence-specific patterns of articulation. For example, we attributed some of the sequence-

specific variability in diphthong and hiatus production to the articulatory properties of the non-

high vowel ([a,e,o]) in the sequences. We suggested that the longer tongue/jaw trajectories

required for sequences with the low vowel [a], were responsible for the longer duration of these

sequences overall as well as a smaller degree of difference between diphthongs and hiatuses with

[a]. This, we claimed, resulted in more sequences with [a] being misclassified as exceptional

hiatuses (in the case of expected diphthongs) or diphthongized hiatuses (in the case of expected

hiatuses). We also found that some speakers maintained a more extreme acoustic difference

between Diphthong and Hiatus. We suggested that this was a direct result of different speakers

using different articulatory strategies to produce vocalic sequences in general and to achieve the

diphthong-hiatus contrast more specifically (Colantoni & Limanni, 2010; McDougall, 2004,

2006). However, these claims are, so far, untested.

The topic of the articulatory properties of vocalic sequences in Spanish (Chitoran & Hualde,

2007) and other Romance languages (Marin, 2007, for Romanian; Zmarich et al., 2012 for

Italian) has received considerable attention recently. Two main claims regarding these sequences

emerge from the literature. The first claim is that the difference between diphthongs and hiatuses

(or between glides and vowels, by extension) can be found in the timing of these gestures. That

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is, diphthongs and hiatuses are thought to differ in their gestural coordination patterns (Chitoran

& Hualde, 2007; Marin, 2007). Proponents of this approach expand on work on the gestural

coordination of consonant-vowel (CV) and vowel-consonant (VC) sequences (e.g. Browman &

Goldstein, 2000). They propose that diphthongs, like CV sequences, are characterized by a

synchronous coordination mode while hiatuses are characterized by a sequential coordination

mode as in vowel-consonant (VC) sequences (Chitoran & Hualde, 2007, p. 61). Gick (2003) uses

this characterization to distinguish the velar onglide from the corresponding velar offglide in

English but its application to the differences between diphthongs and hiatuses remains unclear.

The second claim requires the assumption that glides consists of two gestures, a consonantal or

C-gesture and a vocalic gesture or V-gesture (as found for the English velar glide [w], Gick

(2003). Proponents of this approach maintain that the difference between glides and vowels

occurs because glides have greater C-gesture constriction (Nevins & Chitoran, 2008). In support,

they cite phonological evidence, such as for glide-consonant alternations (Nevins & Chitoran,

2008) that these constriction patterns occur for both velar and palatal glides. Experimental

studies (Zmarich et al., 2012 for Italian; Gick, 2003 for English) suggest that this may be the case

for velars (i.e. the [u]-[w] distinction). However, it remains unclear whether this can be applied

to the behaviour of palatals (i.e. the [i]-[j] distinction) since there is no strong phonetic evidence

of the presence of a C-gesture for the palatal glide [j] (Gick, 2003). More importantly for the

present study, these claims are untested for Spanish.

In the present chapter we put these claims to the test via the examination of the nature of the

speaker-specific and sequence-specific articulatory patterns of diphthongs (Diphthong) and

hiatuses (Hiatus) in this variety of Spanish. Specifically, we conduct an experiment which

investigates the nature of the relationship between vocalic gestures (synchronous or sequential)

in diphthongs and hiatuses by providing direct articulatory movement data on glide-vowel (jV,

diphthongs) and high vowel-vowel (íV, hiatuses) sequences. To achieve this objective, the

experiment tests three hypotheses regarding these sequences. The first hypothesis focuses on

timing. That is, we propose that the difference between jV (diphthongs) and íV (hiatuses)

sequences lies in the relative timing of the articulators which constitute glides and vowels. Based

on Nevins & Chitoran (2008) and expanding on Gick (2003) the assumption is made that the

relevant articulators for these sequences are the tongue body (TB), which constitutes a V-gesture,

and the tongue tip (TT) which constitutes a C-gesture. If diphthongs are indeed phased in a

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synchronous mode and hiatuses in a sequential mode (Chitoran & Hualde, 2007) we should find

a greater temporal offset between the C-gesture and the V-gesture in hiatuses38

. We also expect

speech rate to have some influence on offset values since, as reported in Chapter 3, a faster

speech rate resulted in a decrease in duration for both diphthongs and hiatuses. This duration

reduction can be interpreted as stemming from an increase in the degree of gestural overlap as a

result of the faster speech rate (Browman & Goldstein, 1992). Thus, we expect that this decrease

in duration at the faster speech rate will be reflected in a decrease in offset values. However,

because this phonetic reduction affects all vowel sequences, we expect category distinctions to

be maintained across speech rates (Aguilar, 1999).

Hypothesis 1: Timing hypothesis

Diphthongs and hiatuses differ in the relative timing of TB and TT gestures. The

temporal offset between TB and TT is greater for hiatuses than for diphthongs,

with hiatuses showing a C-gesture (TT) lag. These offset values decrease for all

sequences as speech rate increases but the differences between Diphthong and

Hiatus are maintained.

We might also expect a reduction in the magnitude of the C-gesture for hiatuses relative to

diphthongs if, as put forth by Nevins and Chitoran (2008), glides differ from vowels in having a

greater constriction degree for the C-gesture (see also Padgett 2008, p. 1944). Related to this is

the possibility that the difference between Diphthong and Hiatus is found in the relative

magnitude of either the consonantal (TT) or the vocalic (TB) gestures (Nevins & Chitoran, 2008,

p. 1994) such that for hiatuses the TB dominates while for diphthongs the TT is dominant.

Therefore, the second hypothesis refers to these presumed spatial differences between Diphthong

and Hiatus. To test this hypothesis, we look at the magnitude of both the C-gesture (TT) and the

V-gesture (TB) for diphthongs and hiatuses. Speech rate is also expected to have some influence

on this measure since an increase in speech rate has been shown to produce a reduction in

articulatory displacement for vowels (e.g. Gay, 1974), which may have acoustic consequences

(i.e. be associated with more centralized first and second formant (F1-F2) values). On the other

hand, variations in articulatory patterns do not necessarily produce acoustic consequences (e.g.

Guenther et al., 1999). In the data presented in Chapter 3, for example, we found no consistent

significant differences according to speech rate in F1-F2 values. However, that finding does not

preclude the possibility that the magnitude of articulatory displacement will show a significant

38 This requires the assumption that the initial [i] of a hiatus (like the initial [j] of a diphthong) involves the action of the TT.

123

decrease with an increase in speech rate, since individual speakers may use different strategies to

achieve the required speech rate contrast. That is, to achieve the faster speech rate, they may

decrease movement duration or magnitude, or both (Van Lieshout & Moussa, 2000).

Hypothesis 2: Spatial hypothesis

Diphthongs and hiatuses differ in (i) the magnitude of TT displacement and (ii)

the relative magnitude of TT and/or TB displacement. Diphthongs have greater

TT (C-gesture) displacement than hiatuses while hiatuses have greater TB (V-

gesture) displacement. The magnitude of TT and TB displacement decreases for

all sequences as speech rate increases but the difference between Diphthong and

Hiatus is maintained.

We expect both the gestural timing (Hypothesis 1) and magnitude of TT and TB displacement

(Hypothesis 2) to be affected by the identity of the non-high vowel (V) in the sequence. Based on

the results from the acoustics experiment in Chapter 3, we predict that sequences with [a]

(because of the greater tongue/jaw trajectory between [j]/[i] and [a]) will have more extreme

values than sequences with either [e] or [o] on both the timing and spatial measures. Similarly,

on both relative timing and displacement measures, we predict that the difference between

Diphthong and Hiatus will be smaller for sequences with [a]. For both hypotheses, we also

examine the individual variation in the production of these vowel sequences. This leads us to our

third hypothesis.

Hypothesis 3

Individuals may use distinctive patterns of articulation to produce diphthongs and

hiatuses and to achieve the diphthong-hiatus contrast. For example, individual

participants may differ in their preference for either a timing strategy or a spatial

strategy (or both to some degree). These individual patterns of articulation give

rise to sequences whose category membership is ambiguous (e.g. exceptional

hiatuses).

The chapter is structured as follows. The experiment methodology follows this introduction in

§2. The results are given in §3 and discussed and evaluated against the above hypotheses in §4.

The chapter conclusions are given in §5. The final section also motivates the perception chapter

which follows.

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2.1 Participants

Eight of the ten female native speakers of Mexican Spanish who participated in the acoustic

study took part in the present study. They include AA, AM, AN, CG, DH, KR, LL and MM.

Their participation in both experiments makes it possible to test the proposal that individual

differences in the acoustic production of diphthongs and hiatuses reflect individual differences in

articulatory strategies.

2.2 Stimuli

The materials used for this experiment consisted of the same 40 real words (Appendix 1) used in

the acoustics experiment reported in Chapter 3. As before, 20 words contained the target

sequences: (i) hiatus [í.a], [í.e], [í.o] and (ii) diphthong: [já], [jé],[jó] 39

. The remaining 20 words

consisted of distractors and practice words. As for the acoustic experiment, the words were

embedded in the carrier sentence Digo X para ti “I say X for you” and production was elicited at

two different speech rates. As in the acoustic study, all diphthongs appear in the first syllable of

the target words and this first syllable is always stressed. For hiatuses, the stressed high vowel

itself is in the first syllable.

2.3 Instrumentation and Procedure

Articulatory data were collected with the use of a three-dimensional (3D) AG500 Electro-

Magnetic Articulograph (EMA) system (Carstens Medizinelektronik GmbH, Lenglern,

Germany)40

. Data collection took place in the Oral Dynamics Lab (Department of Speech-

Language Pathology, University of Toronto) under the supervision of the lab’s Research Officer,

Dr. Aravind Namasivayam. For the purpose of this study, twelve small transducer coils were

attached using surgical adhesive (Isodent, Ellman International Mfg) to the following flesh

points on the participants: upper lip (UL), lower lip (LL), tongue tip (TT, 1cm from the tip of the

39 Although data were collected for both rising and falling sequences in this experiment, only the results of the rising palatal

series are reported here. Similarly, data collected for diphthongs in unstressed syllables is not reported. Thus, the number of

tokens analyzed reflects only rising palatal sequences in stressed syllables.

40 For more detailed explanations of the technical aspects (including system accuracy and noise) and experimental principles

underlying the use of 3D-EMA for the study of speech movements, see Hoole, 1996; Van Lieshout ,2006; Yunusova et al., 2008).

125

tongue), tongue body (TB, 3 cm behind the TT coil), tongue dorsum (TD, as far back as the

participant could tolerate), and right and left cheeks. To track jaw movements, a coil was

attached to the mandibular incisors using a custom thermo-plastic impression (Van Lieshout &

Moussa, 2000) to protect the surface of the teeth and ensure a stable location for the jaw coil.

Reference coils on forehead, nosebridge and behind the ears were subsequently used to align all

movement data and correct for head motion (see Data Processing, §2.4 below). Figure 20 shows

the placement of the coils:

Figure 20. Coil placement for 3D EMA

Prior to the start of the experiment, data was collected using a bite plate to which a 3-axis liquid

bubble level was attached at one end. For this trial (bite plate trial), the participant was instructed

to gently bite down and hold this device in her mouth while the experimenter adjusted the

orientation of her head within the EMA cube until the bubble in the spirit level centered between

the two lines on both the longitudinal axis (movement along the coronal plane) and the lateral

axis (movement along the saggital plane). At the same time, the vertical axis (movement along

the transverse plane) was restrained by gaze fixation at the centre of a 19” LCD monitor placed

126

30” in front of the participant’s eyes. The purpose of this bite plate trial was to establish a global

coordinate system by aligning the participant’s head with the cardinal planes of the body. The

data from this trial was subsequently used to normalize head movements.

Participants were recorded as they read words containing target sequences and distractors. The

list of sentences was randomized and presented to the participants on a computer monitor using

DirectRT presentation software (Empirisoft Corp.). Acoustic recordings were collected

simultaneously with the movement data using the same recording equipment and microphone as

for the acoustic experiment reported in Chapter 3, §2.3 but these recordings are not analyzed for

the present experiment. The participants were given written task instructions displayed on the

computer monitor. In addition, the experimenter was available at all times for clarifications. The

stimuli were presented to the participants according to the same procedure used for the acoustic

experiment (Chapter 3, §2.3). As with the acoustics experiment, the participants were given five

practice trials for each speech rate in order to get used to the task. In addition, participants were

engaged in a short conversation with the experimenter prior to the testing phase in order to get

them accustomed to speaking with the coils in their mouth. The participants repeated each

sentence 3 times consecutively in each trial. Thus the target sentences were produced three times

at two speaking rates. Each speaker produced a total of 40 trials*3 utterances*2 speech rates =

240 utterances. Of these, 120 utterances per participant contained the target sequences analyzed

for the present experiment. However, because of a presentation error, Speaker CG recorded 6

additional tokens, bringing the total number of tokens analyzed to 966 instead of the expected

960 (120 utterances*8 participants = 960 possible tokens for analysis). The entire experiment

lasted approximately two hours (1 hour to attach the coils and 1 hour to perform the reading

task). The participants were given frequent short breaks after every few trials. The purpose of

these breaks was two-fold. First, they allowed the participants to rest, thus reducing fatigue.

Second, the breaks were used to monitor the coils and allowed the experimenter to make

corrections where necessary (e.g. re-attach/replace a coil that had become loose). In addition,

participants were given the opportunity to have a brief pause following each trial. All

participants were compensated for taking part in the experiment.

127

2.4 Data Processing

Position calculations and corrections for head movements were carried out using custom-made

software from the Carstens’ company. This software includes a program (CalPos) which

calculates the position and orientation of each sample and a program (NormPos) which conducts

a sample-by-sample head normalization by rotating and shifting the coordinate system such that

all reference sensors remain in the same 3D location across all samples and trials. The NormPos

program uses a normalization pattern file that is based on a single trial. Therefore, the quality of

the head movement correction for the entire experiment depends on the quality of the data from

the reference sensor coils in that trial. Since the quality of data may not be equally good in all

reference coils (i.e. in the case of coil detachment and/or position tracking errors) more than two

reference sensor coils (typically four) are used to allow for redundancy. For the present study,

the nose bridge (coil #5) and the two sensor coils behind the ears (right ear = coil # 12; left ear =

coil #11) usually had the least amount of noise. Noise levels were determined by accuracy

measurements where 3-dimensional (3D) Euclidean distances between pairs of reference sensor

coils (11-12, 5-12, 4-12, 5-11 and 4-11) were calculated. Smaller average standard deviation for

the 3D Euclidean distances between these pairs mean that the distance between the pairs

remained fairly constant throughout all trials for a session (i.e. static system noise was low)

(Hoole and Zierdt, 2010; Yunusova, et al., 2008). Under ideal conditions, the distance between

the pairs of sensors should remain constant throughout all trials for a given session. The average

static system noise for each subject as a function of reference sensor coils pairs can be seen in

Table 27. The mean value for the 8 speakers in the present study was 0.20 mm across all pairs.

This value represents fairly low system noise41

since, overall, the accuracy of the AG500 system

is expected to be approximately 0.50 mm or less in each dimension (X,Y,Z) (Yunusova et al.,

2008).

41 There is, however, the possibility that regions with greater positional errors may not have been captured by the Carstens’

software measurement protocol (Stella et al., 2012; Kroos, 2012).

128

Table 27. EMA static system noise average SDs (in millimeters), by Speaker

Speaker Mean system noise SD (mm)

AA 0.17

AM 0.13

AN 0.24

CG 0.28

DH 0.15

KR 0.31

LL 0.18

MM 0.16

GROUP MEAN 0.20

2.5 Measurement and Analysis

Following processing, the data were measured and analyzed using a custom-made Matlab

application (EGUANA, Ema Gui Analysis, cited in Neto Henriques & Van Lieshout, 2013). The

application allows for the manual selection of the beginning and end points of the segments of

interest as identified from the acoustic signal. In this case, the points of interest for measurement

corresponded to the Glide/High Vowel-V portion of the target words. Once these points are

selected, the application carries out a number of calculations on the articulators selected for

analysis and creates an output file with the resulting measurements. Three articulators must be

selected and in the present case, these include the Tongue Body (TB), the Tongue Tip (TT) and

the Jaw (JAW). For the present study we cite the following temporal and spatial measurements

made on the vertical (up-down) dimension42

:

(i) Temporal measurements

a. offset (measured in milliseconds) between peak amplitudes of TB and TT

gestures

(ii) Spatial measurements

a. peak magnitude (measured in %) of TT and TB displacement

b. magnitude (measured in %) of TT displacement at peak TB displacement

For the spatial measurements, normalized values were used. Normalization was achieved by

setting the maximum amplitude for the constriction for each trial at 100% and the minimum

constriction at 0%. With regards to the spatial measurements, the second measurement (outlined

in (b) above) was used as an additional measure of TT displacement. This was necessary since in

some cases the peak magnitude of TT displacement during the vocalic sequence was difficult to

42 Measurements were also made on the horizontal (front-back) dimension but are not reported here.

129

measure due to blending (partial or complete) with the TT gesture of a following Coronal

consonant (refer to §3.2 for more details).

Temporal measurements reflect the raw offset measurements in milliseconds. For the present

experiment a TB-TT offset value of zero ms means that the peaks for TT and TB coincide, that is

the TT and TB are phased in a synchronous mode. The greater the temporal offset between TB

and TT, the less ‘in-phase’ the two gestures can be assumed to be. Figure 21 illustrates where the

measurements were taken using the sequence [já] from the word piano as produced by speaker

CG43

. Note that while JAW movement also appears, the influence of the JAW on the other

articulators was minimized via a normalization procedure44

. Thus, the TT and TB movements

cited reflect this reduced contribution of the JAW.

Figure 21. Waveform and articulatory movement data from vertical axis of a token of [já]

from the word piano produced by speaker CG, showing the temporal and spatial

measurements used to analyze the data.

43 The JAW signal (JAW minima and maxima) in combination with the acoustic signal were used for segmentation. These data

were manually checked and corrected if no clearly defined maxima or minima were detected.

44 The procedure used is the estimated rotation method (ERM) developed by Westbury et al. (2002) adapted for 3D EMA (as

described in Neto Henriques & Van Lieshout 2013).

130

The output file created by the application was then imported to an EXCEL worksheet for coding.

The tokens were coded as diphthongs (Diphthong) or hiatuses (Hiatus) as per their expected

production (Sequence Type). The independent variables are as follows (these are the same

variables used in the acoustics experiment, as outlined in Chapter 3, §2.4).

(i) Non-high Vowel (V): [a], [e], [o]

(ii) Speech Rate: Rate 1 and Rate 245

Results were evaluated using Repeated-measures ANOVAs on the statistical program MINITAB

14 (Minitab Inc.), with p level set at .0546

. These results are reported next.

3 Results

3.1 Timing (TB-TT Offset)

In this section we examine the temporal offset in milliseconds between peak Tongue Body (TB)

and peak Tongue Tip (TT) to determine whether there is a difference on this measure between

diphthongs (Diphthong) and hiatuses (Hiatus). In interpreting the offset values, a positive

number for the offset reflects a C-gesture (TT) lag (or a V-gesture lead) while a negative number

reflects a C-gesture (TT) lead (or a V-gesture lag). The closer to zero the offset value, the more

‘in-phase’ we can interpret the C-gesture and V-gesture to be. We predict that the offset values

for hiatuses will be greater (due to a TT lag) than the offset values for diphthongs. A summary of

the descriptive statistics for this measure of TB-TT offset is given in Table 28.

Table 28. Means and SDs of TB-TT offset (ms) for Diphthong and Hiatus, by Speech Rate

Rate 1 Rate 2

Sequence Type Mean SD Mean SD

Diphthong 17.85 58.07 12.22 48.75

Hiatus 33.85 76.10 7.00 77.38

45 Measured in syllables/second, these rates are as follows (as outlined in Chapter 3, §2.3): Rate 1 is approximately 4.7

syllables/second; Rate 2 is approximately 6.4 syllables/second.

46 As in Chapter 3, before the data was submitted to statistical analyses, tests for normality of distribution (Anderson-Darling) and

for equality of variances (Bartlett’s or Levene’s) were carried out to determine whether the data conformed to the requirements of

parametric analyses. Most of the measurements met one or both requirements.

Measurement Normality of distribution Equality of variances

TB-TT offset Diphthong: p=0.386; Hiatus: p=0.129 p=0.00 (Bartlett’s)

%TB Diphthong: p<0.05; Hiatus: p<0.05 p=0.236 (Levene’s) %TT Diphthong: p<0.05; Hiatus: p<0.05 p=0.330 (Levene’s) %TT at peak TB Diphthong: p=0.093; Hiatus: p=0.319 p=0.914 (Bartlett’s)

131

Figure 22 shows the mean temporal offset between the peak TB and TT values for diphthongs

and hiatuses at both speech rates. The figure shows positive mean offset values for both

Diphthong and Hiatus at both speech rates, suggesting that, contrary to our prediction, the C-

gesture (TT) lags the V-gesture (TB) in all sequences, not just for Hiatus. This is contrary to our

prediction that only Hiatus should show a TT lag and suggests that the sequence in Figure 21 is

not representative of the average Diphthong. Figure 22 also suggests that there is a significant

difference in TB-TT offset values between Diphthong and Hiatus, at least at the slower speech

rate, Rate 1. At this rate, the difference is in the expected direction, with Diphthong having a

smaller mean offset value than Hiatus. For Rate 2, the mean values for both Diphthong and

Hiatus are smaller, as expected. The difference between Diphthong and Hiatus is also smaller

and this, too is as predicted. That is, the difference becomes smaller since an increase in speech

rate is expected to create more gestural overlap (e.g. Browman & Goldstein, 1992, p. 172) which

in turn would be expected to decrease the offset values. However, the difference between

Diphthong and Hiatus for Rate 2 is in an unexpected direction, with Hiatus having a smaller

mean offset value than Diphthong.

Sequence Type

TB

-TT O

ffse

t in

mse

c.

(ra

w)

HiatusDiphthong

40

30

20

10

0

HiatusDiphthong

Rate = 1 Rate = 2


Figure 22. Bar chart of mean TB-TT offset (ms) by Sequence Type and Speech Rate

In any case, a repeated-measures ANOVA with factors Sequence Type and Rate fails to find a

statistical significance for either of the main effects or their interaction (Table 29). Part of the

132

reason for this lack of significance surely lies in the fact that offset values for both Diphthong

and Hiatus had a high degree of variability as evidenced by the large standard deviations (Table

28), especially for hiatuses.


(ms), by Speech Rate


Main effects Sequence Type F(1,7) = 0.23 0.648

Rate F(1,7) = 2.08 0.192

Interaction Sequence Type*Rate F(1,7) = 2.48 0.159

Other Speaker F(7,21) = 2.40 0.108

A look at the individual data in Figure 23 highlights what appears to be a lack of consistent

patterning of offset values for Diphthong and Hiatus, despite the fact that there was no

significant Speaker effect47

. Three of the eight speakers (AA, AN and MM) show a stable pattern

of smaller TB-TT offset values for diphthongs and a generally consistent C-gesture (TT) lag for

both Diphthong and Hiatus, for both Rate 1 and Rate 2. Others show this pattern only for Rate 1

(CG) or only for Rate 2 (DH). Of the remaining speakers, some had very small differences

between Diphthong and Hiatus (Rate1: DH, KR and LL; Rate 2: AM and CG). Finally, some

speakers show a C-gesture (TT) lead for some sequences, especially hiatuses (where we would

expect a TT lag). This TT lead is likely causing the lack of significance in the group mean offset

values between Diphthong and Hiatus, especially when the TT lead value is quite large (Rate 1:

AM; Rate 2: KR and LL).

47 Individual means and standard deviations are found in Table A3.1, Appendix 3.

133

TB

-TT O

ffse

t in

mse

c.

(ra

w v

alu

es)

100

0

-100

100

0

-10021

Rate 21

100

0

-10021

AA AM AN

CG DH KR

LL MM

Sequence Type

Diphthong

Hiatus


Figure 23. Bar chart of mean TB-TT offset (ms) for Sequence Type, by Speech Rate and

Speaker

Finally, we observe individual differences in the amount of variability in the data with some

speakers producing quite large standard deviations (refer also to Table A3.1, Appendix 3). The

large amount of individual and group variability suggests that this is either not a good measure of

the articulatory differences between diphthongs and hiatuses or that Diphthong and Hiatus (in

this variety of Spanish and for this set of speakers) do not differ consistently on this measure.

On the other hand, a different visual representation of the individual data does reveal a patterned

distribution of offset values. That is, for all speakers, the offset values for diphthongs are

clustering at or near the zero point (Figure 24), with this clustering becoming more pronounced

at Rate 2 (Figure 25). Hiatuses on the other hand, tend to have greater offset values which are

essentially fanning away from the zero point (at both speech rates) in both directions.

134

Sequence TypeSequence Type

TB

-TT O

ffse

t (m

se

c.)

HD

100

50

0

-50

-100

Speaker

AN

CG

DH

KR

LL

MM

AA

AM

Rate 1

Figure 24. Interaction plot of Mean TB-TT offset (ms) for Sequence Type, by Speaker:

Rate 1

Sequence TypeSequence Type

TB

-TT O

ffse

t (m

se

c.)

HD

100

50

0

-50

-100

Speaker

AN

CG

DH

KR

LL

MM

AA

AM

Rate 2

Figure 25. Interaction plot of Mean TB-TT offset (ms) for Sequence Type, by Speaker:

Rate 2

Diphthong

Diphthong

Hiatus

Hiatus

135

Part of the problem identified with the measure of TB-TT offset is the anticipatory movement of

the TT largely due to the presence of consonants in the stimuli words which involve a Tongue

Tip/Tongue Blade articulation. Because coronal consonants in Spanish are the most frequently

occurring consonants by place of articulation (e.g. Guirao & García Jurado, 1990, p. 144) and

since real words were used in the stimuli set, most of the tokens have a coronal consonant either

preceding or following the vocalic sequence in the word. In the data cited here, consonants

which precede the vocalic sequence do not appear to have a great degree of influence on TB-TT

offset. However, the consonants which follow the vocalic sequences may be a cause for concern

(e.g. Recasens, 1999b, p. 81). Some of these consonants require a high degree of TT involvement

and may be the reason for the TT lag in some of the above sequences. In fact, we find that some

of the participants exhibit this anticipatory effect, especially when the consonant following the

vowel sequence is the lateral, [l] (as in the words viola), the rhotic tap [ɾ] (as in the word diario)

or the fricative [s] (as in the word días)48

. Some speakers had this effect with a following [n],

both when this consonant occurred in a syllable coda (as in the word ríen) or a syllable onset (as

in the word bienio and bienes) but these cases with [n] were fewer and most consistently found

with speakers CG and LL and then mainly for Rate 2. A following dental stop (/t/ and /d/, as in

the words prieto and criada) did not appear to produce this effect as often. This can be explained

by the fact that these consonants appeared in intervocalic position, a position where they are

frequently lenited. For example, the voiced dental stop /d/ is almost exclusively produced as an

approximant [ð] in this position (Hualde, 2005; Martínez-Celdrán, 2008). The voiceless dental

stop /t/ may also be voiced and in some cases have an approximant realization in intervocalic

position (Hualde, 2005; Martínez-Celdrán, 2009) 49

. However, lenition may not be the only

explanation for this there is evidence of intervocalic /n/ lenition in Spanish as well, at least for

Peninsular Spanish (Honorof, 2003). Therefore, another possibility is that the anticipatory TT

movement is influenced by the constriction location and the orientation of the tongue tip of a

following alveolar (Kochetov, personal communication, 2013). That is, the anticipatory TT

48 In Mexican Spanish, especially in the variety spoken by the study participants (from Central Mexico), coda [s] (both in word-

final and syllable-final positions) is pronounced fully and is not generally aspirated as in other Spanish varieties (e.g. Hualde

2005).

49 Some varieties of Spanish appear not to participate in the lenition of intervocalic /t/. These varieties include Argentine Spanish

(Colantoni & Marinescu, 2010) and Colombian Spanish (Lewis, 2001). For Mexican Spanish, there are mixed results. For

example, Lavoie (2001) reports that intervocalic /t/ for 4 male speakers from Northern Mexico “is always a robust voiceless stop”

(p. 153). On the other hand, Lope Blanch (1996, Volume 2, Map 16) reports that for intervocalic /t/ tokens collected in Mexico

City (the variety most closely related to the speech of the participants of this study) 10% are voiced and another 2.5% are both

voiced and ‘weakened’.

136

movement is most likely to occur with alveolar consonants ([ɾ], [l], [n] or [s]) than with dental

consonants ([t] and [d]). Although both sets of consonants are generally considered apical (e.g.

Hualde, 2005), the tip-up gesture for the alveolars may start earlier.

With the lateral, in at least one case this anticipatory effect was observed even when [l] occurred

as part of a consonant cluster and did not immediately follow the vocalic sequence (i.e. in diablo,

speaker KR, Rate 2). This is not be surprising given that long-distance coarticulation effects of

liquids are well-documented (e.g. West, 1999, p. 1904). This anticipatory effect was also more

likely to occur at a faster speech rate. Thus, even speakers who did not produce this effect at the

slower speech rate (Rate 1), may have had examples of it at an increased speech rate (Rate 2).

Examples of both the presence (Figure 26) and absence (Figure 27) of this anticipatory effect on

the TT gesture are shown below, using the token viola [bjó.la] at Rate 2 as produced by speakers

CG and AA, respectively.

Figure 26. Waveform and articulatory movement data (vertical dimension) of a token of

[jó] from viola showing anticipatory TT movement, Speaker CG, Rate 2

anticipatory TT movement

137


[jó] from viola showing TT lead, Speaker AA, Rate 2

In short, the articulatory anticipation of the TT gesture varies from speaker to speaker in terms of

the degree and frequency of the effect as well as in the identity of the following consonants

which appear to trigger the effect. Thus, a measurement which looks at the offset values between

TB and TT without taking into consideration lead or lag may be desirable. Recall that our

primary interest in the present study is in the difference between Diphthong and Hiatus in the

amount of TB-TT offset, regardless of lead or lag. That is, our interest is in the distance from

zero (with zero representing a completely in-phase relationship of TT and TB) rather than the

negative or positive value of the offset when it does not equal zero. Therefore, for the purposes

of this experiment, it might be more appropriate to consider the absolute TB-TT offset values.

Using this transformation, the zero values and positive values in the data are maintained while

the negative values (reflecting a TT lead) are converted to positive values. The descriptive

statistics for this new measure are reported in Table 30.

TT lead

138

Table 30. Means and SDs of TB-TT offset (absolute values) for Diphthong and Hiatus, by

Speech Rate

Rate 1 Rate 2


Diphthong 43.30 42.57 36.59 34.41

Hiatus 73.75 38.13 65.63 41.03

On this measure of absolute TB-TT offset (Figure 28), we obtain the predicted results. That is,

the TB-TT offset at both speech rates is greater for hiatuses than it is for diphthongs.

Additionally, the values decrease slightly for both Diphthong and Hiatus at the faster speech rate,

Rate 2. This pattern is similar to what we saw in the previous chapter for sequence duration

(Chapter 3, §3.1). Thus, although the offset duration decreases for both Diphthong and Hiatus as

speech rate increases, the category difference between Diphthong and Hiatus retains its

constancy at both speech rates. The difference in mean offset between Diphthong and Hiatus, in

fact, is essentially the same at Rate 1 (30.45 ms) as it is at Rate 2 (29.04 ms).

Sequence Type

TB

-TT O

ffse

t in

mse

c.

(ab

so

lute

va

lue

s)

HiatusDiphthong

100

75

50

25

0HiatusDiphthong

Rate = 1 Rate = 2



Rate

139

A repeated-measures ANOVA (Table 31) finds a significant effect of Sequence Type50

. The

decrease in offset at the faster speech rate, however, was not enough for statistical significance.

Thus, no significant effects of Rate or of the Rate*Sequence Type interaction were found.


(absolute values), by Speech Rate



Rate F(1,7) = 3.07 0.123


Other Speaker F (7,21) = 1.11 0.490

The Speaker effect was also not significant. Furthermore, the individual data (Figure 29) now

clearly shows that most speakers follow this general pattern of a larger TB-TT offset for hiatuses,

although for some speakers the difference between Diphthong and Hiatus is smaller than for

others (similar to what we saw for sequence duration in Chapter 3) 51

. For Rate 1, speakers MM

and AN had the largest differences while speaker CG had almost equal values for Diphthong and

Hiatus (with Hiatus slightly smaller than Diphthong, contrary to the general pattern). For Rate 2,

speakers AM, KR and LL had the largest differences and CG once again had the smallest

difference. In addition, we find that for some speakers a speech rate increase does indeed

produce obvious decreases in offset values, either for diphthongs (AM and KR), hiatuses (AA,

AN and MM) or both (CG).

50 All significant p-values in this and all subsequent tables are shaded gray.

51 The individual Means and SDs are found in Appendix 3 (Tables A3.2).

140

TB

-TT O

ffse

t in

mse

c.

(ab

so

lute

va

lue

s) 100

50

0

100

50

021

Rate 21

100

50

021

AA AM AN

CG DH KR

LL MM

Sequence Type

Diphthong

Hiatus



Rate and Speaker

3.1.1 Vowel Effects on Timing of TB and TT

Here we consider the effect of the non-high vowel (V) in the sequences on the TB-TT absolute

offset values. The descriptive statistics are given in Table 32.

Table 32. Means and SDs of TB-TT Offset (absolute values) for Diphthong and Hiatus, by

Speech Rate and V

Rate 1 Rate 2

Sequence Type Vowel Mean SD Mean SD

Diphthong

[a] 42.53 39.17 38.85 33.02

[e] 46.08 44.23 35.43 34.12

[o] 38.26 45.34 34.69 37.89

Hiatus

[a] 67.19 32.89 59.69 40.45

[e] 85.00 47.57 88.91 38.43

[o] 75.63 36.13 55.21 37.31

We expected that both Diphthong and Hiatus would have larger offset values when V is [a] than

when V is either [e] or [o]. In addition, we anticipated smaller differences between Diphthong

and Hiatus when V is [a] than when V is either [e] or [o]. A visual inspection of the absolute

offset values (Table 32, Figure 30) suggests some influence of V. However, the effect of V is not

141

always in the predicted direction. For example, we note that sequences with [e] appear to have

longer TB-TT offset values than sequences with [a] or [o], although this difference is found

mainly for hiatuses. For diphthongs, the three levels of V seem to behave similarly at both

speech rates. In addition, we observe relatively small differences between sequences with [a] and

those with [o], for both Diphthong and Hiatus, especially at Rate 2. Overall then, the first

prediction is not met. The difference between Diphthong and Hiatus does, however, appear to be

influenced by the identity of V. Specifically, at Rate 1 the Diphthong-Hiatus difference is

smallest for sequences with [a] (24.66 ms). Sequences with [e] (with a difference of 38.92 ms)

and [o] (with a difference of 37.37 ms), on the other hand, have larger Diphthong-Hiatus

differences than sequences with [a] but do not differ from each other. At Rate 2, the difference

remains largest for sequences with [e] (53.48 ms). In fact, the Diphthong- Hiatus difference for

sequences with [e] increases considerably for Rate 2, due to an increase in offset values for

hiatuses with [e]. Conversely, the Diphthong-Hiatus differences between sequences with [a]

(20.84 ms) and those with [o] (20.52 ms) become similar at Rate 2, largely due to a decrease in

hiatus offset values for [o]. Overall, then, we have more success with our second prediction,

especially for Rate 1.

TB

-TT O

ffse

t in

mse

c.

(ab

so

lute

va

lue

s)

V [o][e][a]

100

80

60

40

20

0[o][e][a]

Rate = 1 Rate = 2

Sequence Type

Diphthong

Hiatus



Rate and V

142

A repeated-measures ANOVA (Table 33) reveals significant effects of both Sequence Type and

V but no significant effect of Rate. Post-hoc comparisons (Bonferroni) confirm that the main

effect of V is due to a significant difference between sequences with [e] and those with [o] (t = -

2.50, p = 0.043). None of the interactions were significant. In other words, the offset values for

Diphthong were smaller than those for Hiatus across all vowel and speech rate contexts.


(absolute values), by Speech Rate and V


Main effects

Sequence Type F(1,14) = 32.90 0.001

Rate F(1,14) = 1.83 0.219

V F(2,14) = 4.08 0.040

Interactions

Rate*Sequence Type F(1,14) = 0.05 0.837

Rate*V F(2,14) = 0.30 0.660

Sequence Type*V F(2,14) = 2.84 0.092

Rate*Sequence Type*V F(2,14) = 1.64 0.229

Other Speaker F (7,77) = 1.49 0.403

Although the Speaker effect was not significant, the individual data (Figure 31) does show some

between-speaker differences in the realization of Diphthong and Hiatus52

. These differences are

influenced by both V and Rate. Specifically, it appears that the differences in Hiatus between

sequences with [e] and those with [a] and [o] can be attributed to the behaviours of Speakers AA,

CG, and MM. These three speakers have greater offset values for hiatuses with [e] than for

hiatuses with [a] or [o] at both speech rates. In addition, Speakers KR and LL exhibited this same

behaviour for [e] sequences but only at Rate 2. Among the remaining speakers we observe

similar offset values for all the V contexts at both speech rates. Some speakers, however, exhibit

more variable production. For example, speaker LL exhibits a high degree of variability in her

Rate 2 production of hiatuses with [e] and [o]. This same speaker also has smaller offset values

for hiatuses than for diphthongs in sequences with [o] at both speech rates, suggesting a

diphthongized production of these sequences.

52 See Tables A3.3-A3.5 in Appendix 3 for individual means and SDs.

143

TB

-TT O

ffse

t in

mse

c.

(ab

so

lute

va

lue

s)

160

80

0

160

80

0[o][e][a]

V [o][e][a]

160

80

0[o][e][a]

AA AM AN

CG DH KR

LL MM

Sequence Ty pe

Diphthong

Hiatus

Rate = 1

TB

-TT O

ffse

t in

mse

c.

(ab

so

lute

va

lue

s)

160

80

0

160

80

0[o][e][a]

V [o][e][a]

160

80

0[o][e][a]

AA AM AN

CG DH KR

LL MM

Sequence Ty pe

Diphthong

Hiatus

Rate = 2


Rate, V and Speaker

3.2 Spatial Displacement (%TT and %TB)

Here we look at the maximum displacement (expressed as %) achieved by the TT and the TB

within the segment. Table 34 summarizes the descriptive statistics for this.

Table 34. Means and SDs of maximum TT and TB displacement (%) for Diphthongs and

Hiatus, by Speech Rate

Rate 1 Rate 2

Sequence Type Articulator Mean SD Mean SD

Diphthong ,Tonic (D) TB 95.51 10.00 96.72 10.43

TT 86.75 17.67 90.45 17.99

Hiatus (H) TB 98.01 6.81 94.80 12.73

TT 93.64 11.65 96.46 8.48

If glides (as found in diphthongs) are indeed more consonantal than vowels (as found in hiatuses)

(Nevins & Chitoran, 2008), then we would expect the TT (the C-gesture) to reach a higher

maximum displacement for diphthongs than for hiatuses. We might also expect the TB, or V-

gesture to be dominant in hiatuses. On the other hand, if we adopt the view that diphthongs are

moving targets (i.e. they are characterized by their glide’s movement through time, Gay, 1970),

144

we might expect the opposite to occur. That is, glides in diphthongs may exhibit a smaller TT

and TB displacement than the corresponding high vowels in hiatuses. In fact, in Chapter 3, we

reported that diphthongs in general had higher F1 values and lower F2 values than corresponding

hiatuses, especially in the glide portion (see also Borzone de Manrique, 1979 and Aguilar, 1997

for similar findings for Argentine and Peninsular Spanish, respectively). This suggests that glides

appearing in diphthongs are more, rather than less, sensitive to coarticulation from the non-high

V in the sequence and are produced with a more open articulation than their single-target vowel

counterparts. A first look at the data for these two measures (TB and TT vertical displacement)

in Figure 32 (see also Table 34) suggests that glides do, in fact, have smaller TT displacement

than hiatuses, against our initial hypothesis and in support of the moving-target proposal. On the

other hand, the TB displacement for both Diphthong and Hiatus is virtually identical.

Pe

ak D

isp

lace

me

nt

(%)

TTTBTTTB

100

80

60

40

20

0TTTBTTTB

Rate = 1 Rate = 2Sequence Type

Diphthong

Hiatus


Figure 32. Bar chart of mean magnitude of TT and TB displacement (%) for Sequence

Type, by Speech Rate

In fact, we find no significant difference in Sequence Type or Rate between Diphthong and

Hiatus where TB displacement is concerned (Table 35). The Sequence Type*Rate interaction

also failed to reach significance. The interaction, however, did approach significance (p = 0.051)

due to the slightly larger difference between Diphthong and Hiatus for Rate 1. On this measure

of TB displacement we also find a significant Speaker effect.

145

When we look at the magnitude of TT displacement, on the other hand, we find that the

difference between Diphthong and Hiatus is indeed significant. However, it is the hiatuses which

exhibit a higher degree of relative TT displacement, not the diphthongs, as hypothesized. Rate is

also significant since for both Diphthong and Hiatus there is a greater TT displacement at the

faster speech rate (Rate 2). This is also surprising since we might have predicted a reduction, not

an increase, in TT magnitude with an increase in speech rate (e.g. Browman & Goldstein, 1989,

1992). However, a reduction in the magnitude of a gesture need not necessarily accompany an

increase in speech rate. If we consider gestural reduction to be under speaker control (e.g. Jun,

1996; Barry, 1992), it is possible that some speakers may increase TT displacement in order to

counterbalance a large increase in gestural overlap (as measured by a decrease in TB-TT offset

in the present data). We examine this possibility below when we look at the individual results

(Figure 33). The Sequence Type*Rate interaction is not significant. On this measure of

maximum TT displacement we find no significant Speaker effect.

Table 35. ANOVA table for differences between Diphthong and Hiatus in maximum TB

and TT displacement (%), by Speech Rate

%TB %TT

Source F(df term, df error) p F(df term, df error) p

Main effects Sequence Type F(1,7) = 0.13 0.730 F(1,7) = 37.47 0.000

Rate F(1,7) = 0.46 0.519 F(1,7) = 6.93 0.034

Interaction Sequence Type*Rate F(1,7) = 5.54 0.051 F(1,7) = 0.10 0.757

Other Speaker F (7,21) = 5.43 0.046 F (7,21) = 11.90 0.286

When considering the relative magnitude of TT and TB displacement we observe a general

pattern of greater TB displacement relative to TT displacement with the difference between TB

and TT being greater for diphthongs (due to the smaller TT displacement for diphthongs) than

for hiatuses. However, this pattern is reversed for Rate 2 hiatuses. Below we discuss the

individual variation that is likely causing this reverse pattern for Rate 2 hiatuses.

The individual data (Figure 33) generally match the group data53

. That is, we observe very little

difference in TB activity between Diphthong and Hiatus, with the values for both types of

sequences approaching 100% for most speakers. The Speaker effect found on this measure is

53 Individual means and SDs are found in Tables A3.6 and A3.10 in Appendix 3.

146

largely due to speakers KR and LL who have smaller maximum TB displacement for both

Diphthong and Hiatus at both speech rates. This is most obvious for speaker KR with Rate 2

hiatuses. A smaller TB displacement results in KR and LL having a different TB-TT

displacement pattern from the other speakers. That is, where most other speakers have a smaller

TT displacement relative to the TB displacement, speakers KR and LL have the opposite pattern.

In fact, it is probably KR’s behaviour with Rate 2 hiatuses which is responsible for the pattern

observed in Figure 33 (where Rate 2 hiatuses have larger TT displacement relative to TB

displacement). In terms of TT displacement on its own, we find that most of the participants

follow the pattern of slightly greater TT displacement for hiatuses than for diphthongs.

We also find that all the speakers but one (LL) show some degree of increase in TT magnitude at

Rate 2, either for diphthongs only (AN, CG), hiatuses only (DH) or both (AA, AM, MM, KR).

All these speakers had a decrease in TB-TT offset (absolute values, refer to Tables 3 and 4 in

Appendix) either for Diphthong (AM, KR), Hiatus (AA, MM) or both (AN, CG, DH). Speaker

LL, on the other hand had a very small decrease in offset for Diphthong (0.42) at Rate 2 and an

increase in offset for Hiatus at Rate 2. Thus, there may be negative relationship between a

decrease in TB-TT offset and an increase in TT magnitude at the faster Rate. That is, if you have

more of one you may have less of the other. This may be a way of assuring recoverability for the

listener at the faster speech rate (e.g. Flege, 1988). However, the relationship is not completely

clear since the Sequence Type (Diphthong or Hiatus) which undergoes reduction in offset does

not necessarily match the Sequence Type which shows an increase in TT magnitude54

.

54 It is possible that this lack of correspondence between offset reduction and TT magnitude increase may have been influenced

by the use of normalized data for TT magnitude.

147

Pe

ak D

isp

lace

me

nt

(%)

100

50

0

100

50

0TTTBTTTB

TTTBTTTB

100

50

0TTTBTTTB

AA AM AN

CG DH KR

LL MM

Sequence Ty pe

Diphthong

Hiatus

Rate = 1

Pe

ak D

isp

lace

me

nt

(%)

100

50

0

100

50

0TTTBTTTB

TTTBTTTB

100

50

0TTTBTTTB

AA AM AN

CG DH KR

LL MM

Sequence Ty pe

Diphthong

Hiatus

Rate = 2

Figure 33. Bar chart of mean magnitude of TT and TB displacement (%) for Sequence

Type, by Speaker: Rate 1 and Rate 2

Finally, a closer examination of the data reveals a possible reason for the pattern of greater TT

displacement for hiatuses. The explanation can be found in the influence of the following

consonants, just as we saw for the raw values of TT-TB offset (where a following coronal

consonant resulted in an anticipatory TT movement, resulting in a TT lag). That is, another way

in which a following coronal consonant appears to influence a TT gesture associated with a

vocalic sequence is by reducing its magnitude. This effect appears to affect diphthongs more

than hiatuses (whereas the effect on TT lag was reported to affect hiatuses more readily). The

effect is also more obvious as speech rate increases but at both speech rates it is subject to

individual variation. An example of this phenomenon is illustrated below where, by looking at a

larger segment within the word viola [bjóla], produced by Speakers MM and AN, we see the

reduced TT gesture for speaker AN (Figure 34) but not for speaker MM (Figure 35). No similar

effect is observed for TB displacement.

148


[jó] from viola with no reduction of %TT, Speaker MM, Rate 1


[jó] from viola with reduction of %TT, Speaker AN, Rate 1

149

In some cases the effect of the following consonant on TT displacement is large enough that it

becomes difficult to measure the TT peak for the vocalic sequence. Thus, it may be best to avoid

this measure of magnitude of TT displacement and use a different measure. Below, we replace

this measure with one which focuses on the magnitude (in %) of TT displacement at peak TB

displacement (written as TT@TB in figures). That is, we look at how much TT involvement

there is in the sequences when the TB is at its maximum vertical displacement (Slis & Van

Lieshout, 2013). This is a more indirect but possibly more reliable way to measure and compare

TT involvement in the production of vocalic sequences. The descriptive statistics for this

measure are given in Table 36.

Table 36. Means and SDs of TT displacement at peak TB displacement (%) for Diphthong

and Hiatus, by Sequence Type and Rate

Rate 1 Rate 2


Diphthong 74.58 22.13 78.63 25.24

Hiatus 67.91 20.98 72.32 20.66

A preliminary look at the results in Table 36 and Figure 36 shows that the TT achieves a greater

magnitude at peak TB displacement for diphthongs than it does for hiatuses. This holds for both

speech rates. In addition, we find that while TB displacement does not change significantly as

speech rate increases, TT displacement again appears to increase slightly with an increase in

speech rate, both for diphthongs and hiatuses.

150

Pe

ak D

isp

lace

me

nt

(%)

TT@TBTBTT@TBTB

100

80

60

40

20

0TT@TBTBTT@TBTB

Rate = 1 Rate = 2

Sequence Type

Diphthong

Hiatus


Figure 36. Bar chart of mean magnitude of TB displacement (%) and TT displacement (%)

at peak TB displacement for Sequence Type, by Speech Rate

This difference between Diphthong and Hiatus (Sequence Type) on this new measure of TT

displacement at peak TB displacement is statistically significant (Table 37). However, contrary

to our observations, the main effect of Rate was not significant and neither was the Sequence

Type*Rate interaction. Finally, we find a significant Speaker effect.

Table 37. ANOVA table for differences between Diphthong and Hiatus in TT displacement

at peak TB displacement (%), by Speech Rate

%TT at peak TB



Rate F(1,7) = 5.30 0.055


Other Speaker F(7,21) = 19.31 0.000

The individual data (Figure 37) shows that while the degree of difference between TB and TT

displacement varies from speaker to speaker, most speakers follow the general pattern of greater

TB displacement55

. Speakers LL and KR, once again are the only exceptions and the Speaker

55 Means and SD values for individual data are found in Table A3.11, Appendix 3.

151

effect in the data is largely due to differences between these two speakers and the remaining

speakers. For example, Speaker LL has the opposite pattern as the other speakers (i.e. slightly

higher TT displacement) at both speech rates while speaker KR has this higher TT displacement

only for Rate 2 hiatuses.

Pe

ak D

isp

lace

me

nt

(%)

100

50

0

100

50

0TT@TBTBTT@TBTB

TT@TBTBTT@TBTB

100

50

0TT@TBTBTT@TBTB

AA AM AN

CG DH KR

LL MM

Sequence Ty pe

Diphthong

Hiatus

Rate = 1

Pe

ak D

isp

lace

me

nt

(%)

100

50

0

100

50

0TT@TBTBTT@TBTB

TT@TBTBTT@TBTB

100

50

0TT@TBTBTT@TBTB

AA AM AN

CG DH KR

LL MM

Sequence Ty pe

Diphthong

Hiatus

Rate = 2


at peak TB displacement for Sequence Type, by Speech Rate and Speaker

3.2.1 Vowel Effects on Spatial Displacement of TB and TT

In this section we examine the effects of the non-high vowel (V) in the sequences on maximum

TB displacement (TB) and on TT displacement at peak TB displacement (TT@TB). The

descriptive statistics for both measures are given in Table 38.

152

Table 38. Means and SDs of TB and TT displacement (%) for Diphthong and Hiatus by

Speech Rate and V

Rate 1 Rate 2

Sequence Type Articulator Vowel Mean SD Mean SD

Diphthong

TB

[a] 95.12 10.06 97.56 7.71

[e] 97.23 7.34 95.94 12.84

[o] 92.20 13.91 96.83 8.94

TT@TB

[a] 70.45 22.93 75.12 27.71

[e] 77.01 20.09 80.42 23.79

[o] 77.41 24.02 81.59 22.65

Hiatus

TB

[a] 96.96 8.63 94.38 12.29

[e] 99.78 1.02 98.99 2.82

[o] 98.34 5.72 91.61 17.81

TT@TB

[a] 64.52 23.07 72.96 20.57

[e] 69.32 19.29 70.21 22.21

[o] 73.28 17.37 73.07 20.07

In Figure 38, we observe the following differences between Diphthong and Hiatus. First, for all

three levels of V and at both speech rates, the TB displacement is greater than TT displacement

at peak TB. This applies to both Diphthong and Hiatus. Second, we find that for all levels of V,

the TT displacement at peak TB is greater for Diphthong and Hiatus, although this difference is

very small for Rate 2 sequences with [a]. Finally, for all three levels of V and at both speech

rates we observe little difference in TB displacement between Diphthong and Hiatus. Thus, the

observations made in the previous section appear to apply across vowel contexts.

153

Pe

ak D

isp

lace

me

nt

(%)

100

75

50

25

0

21

TT@TBTBTT@TBTBTT@TBTBTT@TBTB

Rate 21


100

75

50

25

0

V = a V = e

V = o

Sequence Type

Diphthong

Hiatus

Rate Sequence Ty



at peak TB displacement for Sequence Type, by Speech Rate and V

The results of repeated-measures ANOVAs are summarized in Table 39. For TB displacement,

we find a significant V effect but no significant Sequence Type or Rate effects. Post-hoc

comparisons (Bonferroni) identify the V difference as occurring between sequences with [e] and

those with [o] (t = -2.710, p = 0.025). Specifically, diphthongs with [e] achieve a slightly greater

TB displacement than diphthongs with [o]. No significant differences exist between sequences

with [a] and those with either [e] or [o]. Among the interactions, only Rate*Sequence Type is

significant, mainly because diphthongs at Rate 1 have slightly smaller TB displacement than

Rate 1 hiatuses. However, a post-hoc comparison fails to reach statistical significance (t = 2.56, p

= 0.075). For TT displacement at peak TB, we find a significant effect of Sequence Type but no

significant effects of Rate or V. Similarly, none of the interactions were significant. The Speaker

effect, however, was significant on both measures.

154

Table 39. ANOVA table for differences between Diphthong and Hiatus in TB displacement

and TT displacement at peak TB (%), by Speech Rate and V

%TB %TT at peak TB

Source F(df term, df error) p F(df term, df error) p

Main effects

Sequence Type F (1,14) = 1.78 0.224 F (1,14) = 30.24 0.001

Rate F (1,14) = 0.27 0.617 F (1,14) = 3.33 0.111

V F (2,14) = 5.53 0.017 F (2,14) = 1.51 0.256

Interactions

Rate* Sequence Type F (1,14) = 6.06 0.048 F (1,14) = 0.05 0.835

Rate*V F (2,14) = 0.11 0.900 F (2,14) = 1.20 0.330

Sequence Type *V F (2,14) = 0.50 0.615 F (2,14) = 0.23 0.798

Rate* Sequence Type *V F (2,14) = 3.16 0.074 F (2,14) = 0.76 0.486

Other Speaker F(7,77) = 9.40 0.000 F(7,14) = 44.67 0.000

The individual data (Figures 39-41) suggests that most speakers have this pattern of similar TB

displacement for diphthongs and hiatuses across V contexts56

. Once again, Speakers KR and LL

may be largely responsible for the significant Speaker effect on this measure since they produce

smaller TB displacement for Rate 2 hiatuses with [o].

For TT displacement at peak TB we observe that while some speakers follow the general of

slightly larger TT displacement for Diphthong than for Hiatus and similar displacement across

vowel contexts, some speakers deviate from this pattern. For example, AA has very little

difference between Diphthong and Hiatus, regardless of V. Others have different behaviours for

different V contexts. For example, AM has lower values for Hiatus when V = [e], similar values

for Diphthong and Hiatus when V = [a] and higher values for Hiatus when V = [o]. Similarly,

CG has smaller values for Hiatus where V = [e] and [o], but larger values for Hiatus where V =

[a].

56 Refer to Tables A3.7-A3.9 (%TB) and A3.12-A3.14 (%TT at peak TB) in Appendix 3 for individual means and SDs.

155

Pe

ak D

isp

lace

me

nt

(%)

100

50

0

100

50

0

21


Rate 21


100

50

0

21


AA AM AN

CG DH KR

LL MM

Sequence Type

Diphthong

Hiatus

Sequence Type Ra

V= [a]


Figure 39. Bar chart of mean magnitude of TB displacement and TT displacement at peak

TB displacement for Sequence Type, by Speech Rate and Speaker, V = [a]

Pe

ak D

isp

lace

me

nt

(%)

100

50

0

100

50

0

21


Rate 21


100

50

0

21


AA AM AN

CG DH KR

LL MM

Sequence Type

Diphthong

Hiatus

Sequence Type Ra

V= [e]



TB displacement for Sequence Type, by Speech Rate and Speaker, V = [e]

156

Pe

ak D

isp

lace

me

nt

(%)

100

50

0

100

50

0

21


Rate 21


100

50

0

21


AA AM AN

CG DH KR

LL MM

Sequence Type

Diphthong

Hiatus

Sequence Type Ra

V= [o]



TB displacement for Sequence Type, by Speech Rate and Speaker, V = [o]

Speakers also differ in the degree of difference between TB and TT displacement. We also note

that while most speakers observe the general pattern of smaller TT displacement and larger TB

displacement, this pattern is reversed in some cases. Speakers KR and LL, in particular, have at

least one example of this reverse pattern for all V contexts. Speaker AM has a single case of this

reverse pattern for Rate 2 hiatuses with [o].

3.3 Discriminant Analysis

We now turn to the question of whether the individual variation found on the timing and spatial

measures results in cases of diphthongs produced as hiatuses (i.e. exceptional hiatuses) and/or

hiatuses produced as diphthongs. As in the acoustics chapter (Chapter 3), we use Discriminant

Analysis (DA) to determine category membership for Diphthong and Hiatus. In this study, the

possible predictors for category membership are: (i) TB-TT offset (absolute values); (ii)

maximum %TB displacement, and; (iii) %TT displacement at peak TB displacement. However,

we can omit the second predictor (maximum TB displacement) since we found no significant

Diphthong-Hiatus difference and no significant V effects with this measure. This mirrors the

decision in Chapter 3 to include only significant predictors in the analysis. In fact, a preliminary

157

analysis which included this predictor produced worse results on the Discriminant Analysis for

all three levels of V than if this predictor was omitted. As in Chapter 3, any Diphthong tokens

misclassified as Hiatus are considered cases of exceptional hiatus. Similarly, any Hiatus tokens

misclassified as Diphthong are considered diphthongized. Although the vowel-related effects

observed in the present chapter were fewer and more subject to individual variation, in order to

maintain consistency with the previous chapter (Chapter 3), we analyze the data for each level of

V separately. This was also done because not all levels of V required the inclusion of both

predictors to obtain the best classification rate. The results of these analyses are given below.

3.3.1 Sequences with [a]

For sequences with this vowel, we obtain the best classification rate when we use both

predictors: TB-TT offset and TT at peak TB. Omitting one or the other predictor (especially TB-

TT offset) lowers the correct classification rates for both diphthongs and hiatuses. Overall,

sequences with [a] had the lowest correct classification rate (just under 70%), similar to what

with found with the acoustic parameters in Chapter 3. This is especially the case for hiatuses. In

fact, the pattern with hiatuses is the opposite of what we observe in the acoustic analysis where

hiatuses were more likely to be correctly identified. Coincidentally, we obtain the same correct

classification rate for diphthongs (71.9%) with the articulatory parameters as we did with the

acoustic parameters in Chapter 3. However, the correct classification rate for hiatuses is much

lower on the articulatory measures (59.4%) than on the acoustic measures (80.8%).

Table 40. Discriminant analysis summary table for V= [a], using TB-TT offset (absolute)

and %TT at peak TB as predictors (articulation)



Diphthong 207 39 0.000 0.401

Hiatus 81 57 0.401 0.000

Total N 288 96 F (2, 378) = 14.40, p = 0.01

N Correct 207 57


TOTALS N = 384 (0 missing values) N Correct = 264 Proportion Correct = 0.688

The results for misclassified diphthongs and hiatuses with [a] are given in Table 41. Among the

expected diphthongs, the words most likely to be misclassified were diario (about 52% of cases)

and criada (about 44% of cases). Although these two words had similar rates of

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misclassification, diario had more misclassified cases in the highest probability category.

Coming in third place is diablo with a misclassification rate of about 23%. These three words

were also the top three in terms of misclassification in Chapter 3. The word with the fewest

misclassified cases was viaje (about 10%). With viaje, however, all the misclassified cases were

in the lowest probability category and they were all contributed by the same speaker, DH. The

results for this word also match the results from Chapter 3, where viaje also the fewest

misclassifications (5%). However, in Chapter 3, Speaker DH did not contribute any of the cases.

Finally, in Chapter 3 the words piada and piano also had few misclassifications (with rates of

15% and 3%, respectively) whereas here their misclassification rates are higher, especially for

piano (20% and 19%, respectively). Among the expected hiatuses, días had the most

misclassified cases (23 of 48 cases, about 48%), although crías also had a high rate of

misclassification (16 of 48 cases, about 33%). Few of these cases (especially for días), however,

fall into the highest probability category for misclassification. Still, the misclassification

numbers are higher here than on the acoustic parameters. This is especially the case for días

which had a misclassification rate of only 12% on the acoustic parameters. The word crías had a

misclassification rate of 25% on the acoustic parameters.


of Diphthong and Hiatus for V = [a] (articulation)

Expected group Word



Diphthong

criada 27 21 8 9 4

diablo 37 11 8 1 2

diario 23 25 8 6 11

piada 38 10 7 1 2

piano 39 9 3 1 5

viaje 43 5 5 0 0

Hiatus crías 16 32 9 3 4

días 23 25 13 9 1

As with the acoustic parameters, there is also a considerable amount of between-speaker

variation with the misclassified cases (Table 42). For example, MM contributed the fewest

misclassified sequences (7 cases: 5 Diphthong and 2 Hiatus) while CG contributed the most

cases (23 cases: 12 Diphthong and 11 Hiatus) with AA coming in at a close second (20 cases: 12

Diphthong and 8 Hiatus).

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Table 42. Summary of misclassified sequences with [a], by Speaker (articulation)

SPEAKER

Expected group Word AA AM AN CG DH KR LL MM

Diphthong

criada 3 5 3 0 0 3 4 3

diablo 0 4 3 2 2 0 0 0

diario 6 4 6 5 2 1 1 0

piada 0 0 0 1 5 3 1 0

piano 3 0 0 4 0 0 0 2

viaje 0 0 0 0 5 0 0 0

Hiatus crías 2 1 1 5 3 1 3 0

días 6 1 0 6 1 4 3 2

TOTAL 20 15 13 23 18 12 12 7

3.3.2 Sequences with [e]

For sequences with [e], we obtain the best classification rate using only TB-TT offset as a

predictor (Table 43). Including TT at peak TB as a predictor produces slightly worse overall

results (75.5%) mainly due to a drop in correct identification rate for hiatuses (70.2%).

Diphthongs appear to be less affected by the inclusion of this second factor and maintained a

correct classification rate of 76.3%. Overall, sequences with [e] had the highest rate of correctly

classified sequences. Once again, on the articulatory parameters, hiatuses had a worse correct

classification rate than diphthongs.

Table 43. Discriminant analysis summary table for V= [e], using TB-TT offset (absolute) as

predictor (articulation)



Diphthong 252 13 0.000 1.317

Hiatus 77 34 1.317 0.000

Total N 329 47 F (1, 374) = 54.16, p = 0.01

N Correct 252 34



The results for misclassified diphthongs and hiatuses with [e] are summarized in Table 44.

Among the expected diphthongs, the word most likely to be misclassified was pliegue, with over

50% of cases (most of which were in the 70% and higher category) misclassified as Hiatus. This

result is surprising since on the acoustic parameters this word had considerably fewer

misclassified cases (approximately 20% of cases). This inconsistency may reflect errors in the

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acoustic measurements as some tokens of this word were difficult to segment. The word prieto

here also had a large number of misclassifications (approximately 38%) and this number too is

considerably higher than what we observed for this word on the acoustic parameters (where 17%

of cases were misclassified as hiatus). In Chapter 3, we attributed the misclassification rates for

prieto and pliegue reflected to both language–specific as well as cross-linguistic tendencies. For

example, we suggested that the misclassification rates for prieto reflected a tendency for a

preceding [r] to promote hiatus in Spanish (Hualde & Prieto, 2002) as well as a more general

pattern of cross-linguistic avoidance of [j] after rhotics (Van der Beer, 2006; Hall & Hamann,

2010). Similarly, we suggested that the misclassification rate for pliegue reflected the instability

of consonant + lateral clusters in Romance (e.g. Colantoni & Steele, 2005). Finally, we

suggested that both prieto and pliegue, may simply reflect a more general tendency to avoid

diphthongs (i.e. a complex nucleus) after a complex onset. However, we could not explain why

cliente, a word which also has a complex consonant + lateral onset and which is derived from a

Latin heterosyllabic sequence should have fewer misclassified cases than pliegue. Here, we

suggest that the asymmetry between pliegue and cliente follows from articulatory factors.

Specifically, it is related to the place of articulation of the onset clusters in these words (Chitoran

et al., 2002). In cliente, the cluster follows a back-to-front order of constriction location while in

pliegue the order is front-to-back. In stop-stop clusters (Chitoran et al., 2002), the back-to-front

order has been shown to result in less gestural overlap (i.e. greater temporal lag) between the

stops than the front-to-back order. The greater temporal lag in the [kl] cluster of cliente may be

enough to counteract the decreased lag between the second consonant in the cluster and the

following vowel, an effect which has been shown to occur with consonant clusters (Goldstein et

al., 2007).

Since less gestural overlap results in more recoverability for the first element in the cluster,

cliente can have a diphthong following the cluster. However, if the reduced lag between p+l and

l+j in pliegue is enough to threaten recoverability of [p], then it’s possible that the speakers

repair this situation by increasing the overlap between the lateral and the following glide,

resulting in a hiatic pronunciation. The word viejo here has no misclassified cases. This too is

consistent with the acoustic results, where viejo had the fewest misclassified cases. However, on

the acoustic parameters, viejo tied with pieza for fewest misclassified cases. On the articulatory

parameters, on the other hand, pieza has several misclassified cases (about 29%) with most of

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these falling in the highest probability category. Interestingly, the word bienio here has fewer

misclassified cases (about 8%) than with the acoustic parameters (almost 50%). Moreover, it has

fewer misclassified cases here than bienes (at about 19%). This last result is the opposite of what

we would expect given the well-documented hiatic tendency for bienio (e.g. Chitoran & Hualde,

2007) and our results for these words in Chapter 3 (where bienes had a misclassification rate of

15% while the misclassification rate for bienio was approximately 50%). The word ríen, an

expected hiatus, here had a misclassification rate of approximately 28%, also higher than what

we observed on the acoustic parameters (where it was 10%).


of Diphthong and Hiatus for V = [e] (articulation)

Expected group Word



Diphthong

bienes 39 9 2 1 6

bienio 44 4 0 0 4

cliente 41 7 5 2 0

pieza 34 14 2 2 10

pliegue 23 25 3 6 16

prieto 29 18 11 4 3

viejo 42 0 0 0 0

Hiatus ríen 13 34 2 3 8

The between-speaker variation for sequences with [e] is evident in Table 45 with some speakers

clearly contributing more misclassified sequences than others. Here, it is speakers CG, MM and

DH who contribute the most cases (in descending order of number of cases contributed). We also

see patterns of within-speaker variation with some speakers exhibiting results that are consistent

with their results for [a] and other exhibiting less consistent results. For example, among the

three above speakers, MM had the smallest number of misclassified sequences with [a] but the

second highest number with [e]. On the other hand, DH had similar numbers for both vowels

(especially for diphthongs) and CG has the highest number for both vowels.

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Table 45. Summary of misclassified sequences with [e], by Speaker (articulation)

SPEAKER


Diphthong

bienes 3 0 1 2 2 0 0 1

bienio 0 0 0 3 1 0 0 0

cliente 3 3 0 0 1 0 0 0

pieza 0 1 0 5 1 3 3 1

pliegue 1 2 4 4 5 3 0 6

prieto 3 2 3 0 3 2 0 5

viejo 0 0 0 0 0 0 0 0

Hiatus ríen 0 1 2 2 0 3 4 1

TOTAL 10 9 10 16 13 11 7 14

3.3.3 Sequences with [o]

The results for this vowel (Table 46) in terms of the articulatory parameters used as predictors

are similar to those obtained with [e]. That is, we obtain slightly better classification results by

omitting TT at peak TB as a predictor than we do by including it. Its inclusion lowers the overall

correct classification rate to 73%. The correct classification rate for diphthong also lowers

(75.2%). Hiatuses, however, are not affected by the inclusion of the second factor and maintain

the same classification rate (66.7%). As with sequences with [a] and [e], diphthongs fared better

than hiatuses on the correct classification rate.

Table 46. Discriminant analysis summary table for V= [o], using TB-TT offset (absolute) as

predictor (articulation)



Diphthong 109 16 0.000 0.508

Hiatus 32 32 0.508 0.000

Total N 141 48 F (1, 374) = 26.71, p = 0.01

N Correct 109 32



Among the expected diphthongs with [o] (Table 47), piojo had the fewest misclassified cases (3

of 48, around 6%). This concurs with the results for this word on the acoustic parameters, where

no instances of piojo were misclassified. For criollo and viola, on the other hand, we get higher

rates of misclassification here than in Chapter 3. Here, about 29% instances of criollo were

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misclassified while in Chapter 3 we reported a rate of about 8.5%. Similarly, the word viola

which had a misclassification rate of 5% on the acoustic parameters here appears to have a 33%

misclassification rate. The expected hiatus ríos also has a very high misclassification rate here

(33%) compared with the acoustic parameters reported in Chapter 3 (4%).


of Diphthong and Hiatus for V = [o], (articulation)

Expected group Word



Diphthong

criollo 34 14 3 3 8

piojo 45 3 0 0 3

viola 30 15 2 3 10

Hiatus ríos 16 32 8 4 4

Table 48 shows that Speakers AA, AM and CG contributed the highest numbers of misclassified

diphthongs while Speaker LL contributed the highest number of misclassified hiatuses.

Table 48. Summary of misclassified sequences with [o], by Speaker (articulation)

SPEAKER


Diphthong

criollo 4 3 1 1 1 0 2 2

piojo 1 0 0 0 1 1 0 0

viola 0 3 4 5 1 0 0 2

Hiatus ríos 2 3 1 3 0 1 6 0

TOTAL 7 9 6 9 3 2 8 4


In this section we provide a summary of the findings of the study and evaluate whether the

results confirm our hypotheses. We also discuss how these results relate to our findings in the

acoustics study reported in Chapter 3 and to previous articulatory studies.

4.1 Hypothesis 1: Timing of TB and TT

Hypothesis 1 stated that diphthongs and hiatuses in Mexican Spanish differ in the relative timing

of TB and TT gestures. We predicted that the temporal offset between TB and TT would be

greater for hiatuses (Hiatus) than for diphthongs (Diphthong). We also predicted that these offset

values would decrease for all sequences as speech rate increases but that the differences between

Diphthong and Hiatus would be maintained. Our predictions were partially confirmed. That is,

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we found that category membership of Diphthong and Hiatus may indeed be defined by degree

of TB-TT offset, with diphthongs having smaller offset values than hiatuses. However, although

we observed that all sequences experienced a decrease in offset with an increase in speech rate,

the difference was not enough to reach statistical significance. Thus, based on our results, only

the proposed Diphthong-Hiatus difference in TB-TT offset is confirmed; no Rate effects can be

established.

However, in order to achieve the above result for the Diphthong-Hiatus contrast, the original

offset measure had to be modified. We found that the raw TB-TT offset was highly susceptible

to the effects of neighbouring coronal consonants. Thus, in order to capture the expected

differences between Diphthong and Hiatus we used absolute TB-TT offset values instead. We

revisit the benefits and drawbacks of using absolute offset values in the Discussion in §4.4.

These differences in absolute TB-TT offset between Diphthong and Hiatus also appear in

different degrees according to the identity of the non-high vowel (V) in the sequence. We

predicted that sequences with [a] would have larger offset values than sequences with either [e]

or [o]. Similarly, we expected that the difference in offset between Diphthong and Hiatus would

be smallest for sequences with [a]. In fact, only the second prediction was confirmed, mainly due

to the behaviour of hiatuses. Offset values for diphthongs, on the other hand, were similar across

both Vowel and Rate contexts.

Finally, the differences in TB-TT absolute offset between Diphthong and Hiatus are also subject

to individual variation. For example, while most speakers follow the general pattern of a larger

TB-TT offset for hiatuses, some speakers maintain a larger difference between Diphthong and

Hiatus than others, either for Rate 1 or Rate 2. However, most speakers also exhibited variability

in TB-TT offset according to V, especially for hiatuses (§3.1.1).

4.2 Hypothesis 2: Magnitude of TT and TB Displacement

Here we looked at the vertical displacement of the TT and TB for diphthongs and hiatuses. We

predicted that diphthongs would exhibit a greater TT (the C-gesture) displacement while hiatuses

would have a greater TB (the V-gesture) displacement. We also predicted that the magnitude of

TT and TB displacement would decrease for all sequences with an increase in speech rate but

that the differences between Diphthong and Hiatus would be maintained. Our predictions were

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only partially confirmed. We begin with TB displacement. On this measure, our prediction of a

Diphthong-Hiatus difference in TB displacement was not confirmed. Specifically, it was found

that the TB achieved a similar maximum displacement (close to 100%) for hiatuses and for

diphthongs. Overall, TB displacement also appears to be fairly resistant to Rate effects. In terms

of V effects, we find that sequences with [e] achieve a slightly greater TB displacement than

sequences with [o]. Thus, we fail to find the predicted difference between sequences with [a] and

those with [e] and [o]. Finally, it is on this measure that speakers exhibit the most homogeneous

behaviour. That is, none of the speakers had much difference in TB displacement between

Diphthong and Hiatus. They also generally maintained this pattern across V and Rate contexts.

On the other hand, we found differences between diphthongs and hiatuses in TT displacement.

However, because our original measure (maximum %TT displacement appeared to be affected

by a following coronal consonant, these differences were not in the expected direction for the

Diphthong-Hiatus contrast. That is, we found greater TT displacement for hiatuses than for

diphthongs. Thus, we employed a similar strategy as with TB-TT offset and used an alternate

measure of TT involvement, TT displacement at peak TB displacement (given as TT@TB in

figures). On this new measure, we obtained the predicted results: diphthongs had greater TT

displacement at peak TB displacement than hiatuses, across V contexts. Although not

statistically significant, we also found that TT displacement at peak TB displacement tended to

increase slightly at the faster speech rate (Rate 2) for all levels of V and for both Diphthong and

Hiatus. We also found more between-speaker variability than for TB displacement. For example,

some speakers deviate from the pattern of slightly greater TT displacement for Diphthong than

for Hiatus. That is, they produce a very small difference between Diphthong and Hiatus, either

for some V contexts or across all V contexts. We discuss the significance of these findings as

well as the relationship between individual patterns of increases in TT displacement at the faster

speech rate and their possible relationship to decreases in TB-TT offset in the Discussion in §4.4.

4.3 Hypothesis 3: Exceptional Hiatuses

Hypotheses 3 predicted that individual variation in the production of diphthongs and hiatuses

would be reflected in distinctive patterns of articulation which we defined as a preference for

using either a timing strategy or a spatial strategy (or both) to achieve a contrast between

diphthongs and hiatuses. We also predicted that these individual patterns of articulation would

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give rise to sequences whose category membership is ambiguous, as in the case of exceptional

hiatuses. To test this second part of the hypothesis, we used Discriminant Analysis to categorize

sequences as Diphthong and Hiatus according to the articulatory parameters identified as

significant (in this case TB-TT offset and TT displacement at peak TB). We further predicted

that the misclassified cases found in the present chapter (defined by articulatory parameters)

would correspond to those found in Chapter 3 (defined by acoustic parameters). Based on the

findings in both chapters, we also expected that: (i) at the group level, sequences with [a] would

have more misclassified cases than sequences with either [e] or [o], and that (ii) at the individual

level, those speakers with the smallest Diphthong-Hiatus differences, either in TB-TT offset or

TT displacement at peak TB displacement (or both) would contribute the most misclassified

cases.

The first part of the hypothesis was confirmed: we indeed found individual variation in the

production of diphthongs and hiatuses, with the variation appearing on one or both of the

parameters considered. As summarized in §4.1, on the timing measure (TB-TT offset, absolute)

some speakers produce larger differences between Diphthong and Hiatus. Similarly, as

summarized in §4.2, some speakers produced smaller differences between Diphthong and Hiatus

on the spatial measure of TT displacement at peak TB displacement, although the values

sometimes differed according to V context.

We also find that sequences with [a] are more likely to be misclassified than sequences with [e]

or [o]. In addition, we observe that among the speakers who contributed the most misclassified

sequences where V = [a] were generally those who were identified as having relatively small

Diphthong-Hiatus differences, either for TB-TT offset (§3.1), TT displacement at peak TB

(§3.2), or both. This includes speakers AA and CG. Similarly, speakers who were identified as

having larger differences between diphthongs and hiatuses on one or both of these measures

contributed fewer misclassified cases. This includes MM, in particular, but also KR and LL to a

lesser extent. However, we also observe that the relationship between a large Diphthong-Hiatus

difference and fewer misclassified sequences does not always hold. For example, we find that

Speaker DH, who had a large Diphthong-Hiatus difference on the measure of TT displacement at

peak TB (§3.2), also contributed several misclassified cases.

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In summary, the overall results for sequences with [a] are in general in line with what we

observed in Chapter 3. That is, sequences with [a] had a larger number of misclassified cases

than sequences with either [e] or [o]. Secondly, the three words most likely to be misclassified on

the acoustic parameters (diario, diablo and criada) were also the top three misclassified on the

articulatory parameters. Finally, speakers with small Diphthong-Hiatus differences tended to

contribute more misclassified sequences but, as in Chapter 3, this relationship did not always

hold. At the level of individual speakers we also find several matches. For example, Speakers

KR, LL and MM contributed fewer misclassified diphthongs on both the acoustic and

articulatory parameters than other speakers. Similarly, speakers CG, AM and DH contributed

more misclassified sequences with [a] than other speakers on both acoustic and articulatory

measures. However, for some speakers, there was no match. For example, KR had no

misclassified sequences on the acoustic parameters but on the articulatory parameters she had 14

misclassified diphthongs and 4 misclassified hiatuses.

For sequences with [e], we achieved the highest overall correct classification rate and the highest

correct classification rate for hiatuses. Here it is speakers CG, MM and DH who contribute the

highest number of cases. However, these speakers do not necessarily have small Diphthong-

Hiatus differences for sequences with [e]. This list also highlights patterns of within-speaker

variation. For example, some speakers produced results for sequences with [e] that are consistent

with their results for [a] (speakers CG and DH). On the other hand, MM had less consistent

results. Specifically, she had the smallest number of misclassified sequences with [a] but she

contributes the second highest number of cases for [e] sequences. Both the group and individual

results for sequences with [e] differ somewhat from what we observed in Chapter 3. First, on the

acoustic results it was sequences with [o], not [e], which had the smallest number of

misclassified sequences. Secondly, while some of the misclassified words had similar results on

both articulatory and acoustic parameters (i.e. prieto, viejo, bienes), others had much different

results. For example, pieza had several misclassified cases on the articulatory parameters but

only a single case on the acoustic parameters. The word bienio had the opposite behaviour, with

few misclassified cases on the articulatory parameters and several cases on the acoustic

parameters. For the individual results, we also find differences. For example, MM, DH and CG

had very few misclassified sequences with [e] on the acoustic parameters whereas on the

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articulatory parameters they contribute the highest numbers. Conversely, AM had more

misclassified sequences with [e] on the acoustic parameters than on the articulatory parameters.

For sequences with [o], speakers AA, AM and CG contributed the highest number of

misclassified diphthongs. All these speakers tended to have higher numbers of misclassified

cases across vowel contexts, especially CG. Again, these are not necessarily the speakers with

the smallest Diphthong-Hiatus difference for sequences with [o]. For sequences with [o] we also

find both differences and similarities with our results in Chapter 3. For example, on both acoustic

and articulatory measures, piojo had the fewest misclassified cases and criollo and viola had

similar numbers of misclassified cases. However, the misclassification rates were higher on the

articulatory parameters, most noticeably for criollo and viola.

4.4 Discussion

The results summarized above are generally in agreement with what has been proposed in the

theoretical and experimental literature. They also largely coincide with our findings in the

acoustics experiment presented in Chapter 3. However, there are some crucial points where our

findings appear to be at odds with previous research as well as our results from Chapter 3.

First, we presented evidence of TT involvement (in particular, TT displacement at peak TB

displacement, §3.2.3) in the production of both diphthongs (Diphthong) and hiatuses (Hiatus) in

the Mexican variety of Spanish. This suggests, albeit tentatively, that the initial high vocoids of

these sequences ([j] for Diphthong and [i]for Hiatus) consist of both a C-gesture (Tongue Tip,

TT) and a V-gesture (Tongue Body, TB). This finding is in support of the proposal of Nevins &

Chitoran (2008). At the same time, this evidence suggests that palatal glides (as well as high

front vowels) in Spanish may differ from their English counterparts for which no C-gesture has

been confirmed (Gick, 2003).

Second, we found that diphthongs and hiatuses may be differentiated according to (i) the relative

timing of C-gesture and V-gesture (Chitoran & Hualde, 2007), and (ii) the degree of constriction

of the C-gesture (Nevins & Chitoran, 2008). In terms of timing, we reported that the C-gesture

and the V-gesture are timed or phased more closely together in diphthongs than in hiatuses. This

is as proposed by Chitoran & Hualde (2007). It is also in line with our finding in Chapter 3 that

diphthongs are shorter than hiatuses. In terms of degree of constriction, we found the C-gesture

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achieved a greater constriction degree for diphthongs than for hiatuses. This is as proposed by

Nevins and Chitoran (2008). Both results are also in agreement with articulatory studies of

Spanish palatal glides (as found in diphthongs) and high front vowels (as found in hiatuses). For

example, Recasens (1985, 2004) and Recasens et al. (1997) report that both the palatal glide [j]

and the high vowel [i] are highly constrained due to the substantial tongue dorsum contact they

require in their articulation (Recasens et al., 1997). However, glides, due to their “narrower

constriction”, are “more constrained and more resistant to coarticulatory effects than their vowel

counterparts” (Recasens, 2004, p. 165). Our results for C-gesture maximum vertical

displacement agree with these findings. In our data, however, it is the action of the TT at peak

TB displacement which constrains the glides, not the tongue dorsum or tongue body, as in

Recasens (2004) and Recasens et al. (1997). In fact, we found no difference between Diphthong

and Hiatus in terms of TB constriction, either at the group level or the individual speaker level.

This dissimilarity may be the result of the technique used to measure lingual activity. Recasens et

al. (1997) use electropalatography (EPG), a technique which captures the degree of contact

between the tongue and the palate. However, this technique may not reflect the full extent of

activity of the TT as separate from TB activity (Fitzpatrick & Ní Chisaide, 2002). In any case,

our results for TB-TT offset also suggest that vowels (in hiatuses) are less constrained and more

subject to coarticulatory effects from a following coronal consonant as well as from the non-high

vowel (V) in the sequence. Our Discriminant Analysis results appear to confirm this since more

hiatuses are misclassified as diphthongs than vice versa. This supports the observation of a

general diphthongization trend across Spanish varieties (e.g. Hualde et al., 2008; Garrido, 2007).

However, it contrasts with our findings in Chapter 3 where we found diphthongs more likely to

be misclassified than hiatuses as well as be more susceptible to the influence of the non-high

vowel in the sequence.

Third, we found instances of both sequence-specific (Aguilar, 1997, 1999; Lindau et al., 1990)

and speaker-specific variability (Colantoni & Limanni, 2010; MacLeod, 2007). As in Chapter 3,

for example, we found that sequences with [a] tended to behave differently from sequences with

[e] or [o]. That is, sequences with [a] had smaller differences between Diphthong and Hiatus and

more misclassified sequences. These results are also consistent with the fact that most cases of

exceptional hiatuses occur when [a] is the non-high vowel in the sequence (e.g. Hualde, 2005;

Chitoran & Hualde, 2007). However, we also observed that the V effects were more pronounced

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on the acoustic measures than on the articulatory measures. In addition, in Chapter 3, V effects

seemed to target diphthongs while in the present chapter, they are associated with hiatuses. In

terms of inter-speaker variability, we found that some speakers maintained a greater difference

between Diphthong and Hiatus either on the temporal or the spatial measure or both. This result

is similar to what we observed in Chapter 3 and to what has been reported by other authors

(Whitley, 1995; McLeod, 2007; Colantoni & Limanni, 2010). In addition, the speakers identified

as having the smallest Diphthong-Hiatus differences on the articulatory measures were the same

speakers who were identified as having small Diphthong-Hiatus differences on one or more of

the acoustic measures. These speakers include: AA, AM and CG. Similarly, speakers with large

Diphthong-Hiatus differences on the acoustic measures tended to have large differences on the

articulatory measures. These speakers include: DH, KR and LL. However, we did not always

find a match. For example, speakers AN and MM had small Diphthong-Hiatus differences on the

acoustic measures but larger ones on the articulatory measures.

Finally, before leaving this section and this chapter, we need to address the matter of

measurement. Two main issues arise in this respect. First, there is the question of difficulty of

measurement. For example, the contextual effects of the neighboring consonants, in particular

the following consonants, as we found, had a great influence on the variability of our

measurements, especially as speech rate increased. This made it difficult to carry out the

measurement and to determine exactly what we were measuring. This issue was also raised in

Zmarich et al. (2012) in their analysis of the differences in offset (between Tongue Body and Lip

Aperture, in that case) between [au] and [ua] in Italian. Those authors opted to not include the

faster speech rate in their analysis. In the present study, we chose a different option. That is, we

adapted our measurements in order to mitigate the effects of following consonants. This choice,

however, leads us to the question of suitability of the measurements we chose. That is, how well

do these measurements capture the Diphthong-Hiatus contrast? To the extent that they do not

coincide with other research and even our own results from Chapter 3, the answer may be “not

very well”. For example, our findings regarding glides as being more constrained seem to be at

odds with what we saw in Chapter 3 where we found that glides in diphthongs had higher F1

values compared to vowels in hiatuses. This would indicate a more open, less constrained

articulation for glides than for vowels, an effect which has also been reported in other acoustic

studies (e.g. Aguilar, 1999). However, this discrepancy may reflect the fact that in the present

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chapter we have reduced the influence of the JAW from our measurements whereas the acoustic

measurements include JAW effects. That is, the increase in F1 observed for diphthongs may

reflect a lower JAW position. However, the TT may still achieve a greater constriction for the

palatal glide than for the high front vowel and this is not reflected in the acoustic measurement.

In fact, the actions of the TT appear to be associated with the diphthongization process more

generally. On both our original measures of raw TB-TT offset and peak TT displacement as well

as on our modified measures of absolute TB-TT offset and TT displacement at peak TB

displacement it is the TT which experiences changes while the TB seems to be more stable.

Thus, even if these measures are not the best or most accurate, they do offer some insight into

how diphthongization and the Diphthong-Hiatus contrast are achieved at the articulatory level

through the actions of the TT. They also provide a clue as to why diphthongs are at once more

stable and more variable than hiatuses. Specifically, even though diphthongs seem to exhibit

more variability acoustically (e.g. MacLeod, 2007), they appear to be more stable at the level of

articulation. This stability may explain the tendency for hiatuses to diphthongize across Spanish

varieties (e.g. Colantoni & Limanni, 2010).

5 Conclusions

In this chapter, we examined the articulatory characteristics of vocalic sequences in Mexican

Spanish. We provided evidence, albeit limited and based on variable data, that the Diphthong-

Hiatus contrast in this variety can be achieved through differences in both the temporal

coordination of lingual gestures (TB and TT) and in the magnitude of articulatory gestures (TT).

Our results are also generally consistent with the hypothesis that the palatal glide is more

constrained than the high front vowel (e.g. Recasens et al., 1997). They are also largely

consistent with the results from the acoustics experiment we reported in Chapter 3. An important

difference with our acoustic results, however, is that hiatuses appear to be more variable at the

articulatory level while diphthongs appear more variable at the acoustic level. We suggested that

this inconsistency can be explained by the fact that here we are looking at the actions of specific

articulators (especially the TT) while the acoustic effects reflect the actions of several

articulators acting together (i.e. they include the contribution of the JAW). In fact, we

highlighted the importance of the actions of the TT which we proposed to be largely responsible

for both the Diphthong-Hiatus contrast and the diphthongization process. Having now examined

the acoustic and articulatory distinctions between diphthongs and hiatuses in Mexican Spanish,

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in the next chapter (Chapter 5) we explore the ways in which these distinctions influence the

perception of these sequences.

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Chapter 5 Perception of Vocalic Sequences in Mexican Spanish

1 Introduction

In the previous two experimental chapters we found sequence-specific and speaker-specific

variability in the production of diphthongs and hiatuses in Mexican Spanish. We found this

variability both at the acoustic level (Chapter 3) and at the articulatory level (Chapter 4). We

attributed the sequence-specific variability to phonetic properties of the non-high vowel (V) in

the sequences. In both chapters, for example, we found that sequences where V = [a] behaved

differently from sequences where V = [e] or [o]. Specifically, Diphthong and Hiatus sequences

with [a] tended to be closer to each other on all measures than their counterparts with [e] or [o].

Consequently, sequences with [a] were more likely than sequences with [e] or [o] to be

misclassified in a Discriminant Analysis procedure. We pointed out that these results are

consistent with the fact that most cases of exceptional hiatuses occur when V = [a] (e.g. Chitoran

& Hualde, 2007). In terms of speaker-specific variability, we found that some speakers

maintained a greater difference between Diphthong and Hiatus than others and that speakers with

large Diphthong-Hiatus differences on the acoustic measures also tended to have large

differences on the articulatory measures. In relation to this, we also observed that those speakers

who maintained a greater Diphthong-Hiatus difference tended to contribute fewer misclassified

Diphthong sequences. However, we also found that this relationship between a large Diphthong-

Hiatus difference and fewer misclassified sequences did not always hold. We also found

substantial intra-speaker variability related to the identity of V. That is, some speakers

consistently maintained a similar acoustic and articulatory distance between Diphthong and

Hiatus across vowel contexts while others behaved differently according to the identity of V.

This variability also tended to influence the number of misclassified sequences each speaker

contributed for each V.

Still, in spite of the fact that some sequences were identified as ambiguous and misclassified by

the Discriminant Analysis procedure, we have not addressed the question of whether these

statistical misclassifications are perceptually relevant to listeners. That is, will they be similarly

subject to misclassification by listeners in a perception experiment? Faber & DiPaolo (1995)

suggest that Discriminant Analysis may indeed be useful in identifying vowel contrasts that are

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perceptually distinctive. In fact, an earlier study by Port & Crawford (1989) on the incomplete

neutralization of the German word-final /d/-/t/ contrast reports “a tendency for native speakers

and discriminant analysis to classify the same tokens the same way” (p. 276). More recently,

Morrison (2006) compared the overall correct identification rates of final /d/-/t/ obtained from

Discriminant Analysis and those obtained from a group of Spanish listeners and found that they

were similar. These findings suggest that listeners are using at least some of the cues utilized in

the Discriminant Analysis. Thus, we can expect to find some degree of similarity between the

sequences misclassified by Discriminant Analysis and those that listeners discriminate or fail to

discriminate in a perception task.

We also have yet to address whether a speaker’s production of misclassified sequences is related

to her perception of these sequences. In other words, is a speaker who produces many

misclassified Diphthong tokens better able to discriminate between Diphthong and Exceptional

Hiatus in a perception task? Previous research supports the likelihood of such a link between

distinctness in production and perceptual acuity. For example, Perkell et al. (2004a) tested

participants’ production and perception of two American English vowel contrasts and found that

those participants who were more accurate in perceiving the contrast (as determined through a

discrimination task) produced the same contrast more distinctly. Perkell et al. (2004b, for

American English) report similar findings for the /s/-/ʃ/ contrast. Newman (2003, for American

English) also finds significant, albeit small, correlations between individual differences in the

production of VOT for stop consonants and spectral peaks for voiceless fricatives and individual

differences in their perception.

Other studies on vocalic sequences, both for Spanish and other Romance varieties have

addressed the issue of the production-perception link identified above (refer to Chapter 2 for a

review of the relevant studies). Overall, these studies provide three main insights. First, they

have shown that listeners, when unsure as to what category of vocalic sequence a stimulus

belongs to, will choose a diphthong syllabification over a hiatus syllabification (e.g. Face &

Alvord, 2004; Cabré & Prieto, 2006, both for varieties of Peninsular Spanish; Gili Favela &

Bertinetto, 1998, for different regional varieties of Italian). This is in support of a generalized

diphthongization pattern across Romance varieties (Chitoran & Hualde, 2007). Second, they

have shown that participants’ perception of these sequences is generally consistent with their

production of the same sequences (e.g. Hualde & Prieto, 2002, for Peninsular Spanish), such that

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speakers who consistently produce certain sequences as hiatuses tend to also identify them as

such in a perception task (either syllabification intuition or labeling). Third, they have suggested

that acoustic differences translate into perceptual differences. For example, Chitoran (2002, for

Romanian) found that the magnitude of acoustic differences found in vocalic sequences can be

used to predict correct identification rates in a perception task. Specifically, her participants

correctly identified sequences at a statistically significant rate when they also differed

statistically on the acoustic parameters measured (i.e. [ja] vs. [ea] sequences in this case). On the

other hand, identification of sequences which did not differ acoustically (i.e. [oa] vs. [wa]) was

roughly at chance level (Chitoran, 2002).

In the present chapter, we combine the insights gained from these previous studies with our own

results from Chapters 3 and 4 to create an experimental perception study which aims to address

the main issues and questions outlined above. We test three hypotheses associated with this

objective. As with the acoustic and articulatory study in the previous two chapters, the present

study focuses on sequences of rising sonority in which the first component is a high front vowel

[i] or a palatal glide [j] and the second component is a non-high vowel (V = [a,e,o]).

The first hypothesis explores possible within-category and between-category variability in the

perception of diphthongs, hiatuses and exceptional hiatuses.

Hypothesis 1

Diphthongs and hiatuses were found to differ systematically and significantly on

both acoustic and articulatory measures. For this reason, we propose that they

belong to different perceptual categories and predict that discrimination between

them will be high. On the other hand, exceptional hiatuses (a subset of the

Diphthong category) pattern with hiatuses on both acoustic and articulatory

measures. For this reason, we propose that exceptional hiatuses are not a separate

perceptual category for this variety of Spanish and predict that discrimination

between Hiatus and Exceptional Hiatus will be low.

The second hypothesis looks at how the quality of the non-high vowel (V) affects the

perceptibility of the sequence.

Hypothesis 2

The quality of V ([a], [e], or [o]) affects the magnitude of acoustic and

articulatory differences found between categories of vocalic sequences, which in

turn affects their perceptibility. Our acoustic and articulatory results suggest that

Diphthong and Hiatus sequences with [a] are perceptually closer to each other

than corresponding sequences with [e] or [o]. Thus, we predict that with

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sequences where V = [a] participants will exhibit more difficulty (i.e. produce

more incorrect responses) in discriminating between Diphthong, Hiatus and

Exceptional Hiatus than they will with sequences where V is either [e] or [o].

The final hypothesis focuses on the association between individual variation in the production

and perception of the vocalic sequences.

Hypothesis 3

Individuals differ in the degree of acoustic and articulatory difference they

maintain between Diphthong and Hiatus. Overall, the findings in Chapters 3 and 4

showed that a smaller difference tended to result in a greater number of

misclassified sequences, especially misclassified Diphthong sequences. As a

result, we propose that participants who consistently produced misclassified

Diphthong sequences (i.e. produced Exceptional Hiatuses) will be better able to

discriminate between Diphthong and Exceptional Hiatus in a perception task than

those who had fewer misclassified Diphthong sequences.

The experimental strategy adopted in the present study differs in some respects from the one

often employed in perception studies on Spanish vowel sequences (e.g. Hualde & Prieto, 2002;

Face & Alvord, 2004; Cabré & Prieto, 2006). Those studies have tended to rely on native-

speaker syllabification intuitions and/or identification tasks to determine whether participants

perceive the contrast between different categories of sequences. In those tasks which focused on

syllabification intuitions, the words to be discriminated were sometimes presented to the readers

in written form, rather than aurally (e.g. Hualde & Prieto, 2002; Cabré & Prieto, 2006). Thus, in

a strict sense, the participants did not really perceive any stimuli. The main concern with this

methodology, however, is that it may be tapping into learned syllabification and be influenced by

orthography and lexical bias. That is, participants who are highly literate may have learned to

judge these sequences differently and may have learned to perceive a difference in syllabification

which they otherwise would not perceive in a purely aural presentation, with the effects of

lexical bias controlled for. In studies that have presented stimuli aurally (e.g. Face & Alvord,

2004) participants have been asked to identify or classify stimuli according to predetermined

categories (i.e. either diphthong or hiatus) with no option for ambiguous stimuli.

Here, an attempt is made to mitigate some of the concerns with the above methodologies as

follows. First, we use nonsense words (refer to §2.2, this chapter, for details) to control the

possible effects of lexical bias. Second, we use an AX same/different discrimination task (e.g.

Beddor & Gottfried, 1995) to test perception of vocalic sequences in Mexican Spanish. In this

type of task (described in more detail in §2.3, this chapter), participants are asked to decide if

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two stimuli presented in a single trial are the same or not, without reference to fixed categories.

This task type was selected over other possible discrimination tasks (e.g. ABX or a dual pair

4IAX57

) because of its low cognitive demand (Beddor & Gottfried, 1995; Gerrits & Schouten,

2004) and ease of presentation. However, the AX task has some potential disadvantages which

needed to be addressed. These include: (i) a bias towards Same responses in cases where

discrimination of the two stimuli is difficult, and (ii) response decisions made on the basis of

stimuli characteristics not relevant to the task. Although likely not eliminated, these potential

problems were controlled in the following ways. First, some of the possible distracting

characteristics of the stimuli58

were controlled by (i) ensuring equal loudness across all stimuli;

using stimuli produced by a single speaker to avoid decisions based on speaker differences, and

(iii) using only intra-vowel comparisons in the stimuli pairs (to avoid decisions based on identity

of V). Second, the listeners participated in a practice session (described in §2.3, this chapter) in

which they became familiar with the stimuli and the task requirements. In this practice session,

they also received feedback about correct responses. The purpose of the feedback was to focus

the listeners’ attention on the relevant differences between the pairs (Werker & Tees, 1984, p.

1872-1873). Finally, signal-detection measures (described in §2.4.1, this chapter) were used to

separate response bias from discrimination performance.

We also test the effect of the duration of the inter-stimulus interval (ISI) on the discrimination of

these vocalic sequences. Studies where ISI duration was varied have reported that a longer ISI

encourages better accuracy in between-category discrimination while a shorter ISI encourages

better accuracy in within-category discrimination (Pisoni, 1973; Werker & Tees, 1984; Werker

& Logan, 1985; Cowan & Morse, 1986; Van Hessen & Shouten, 1992; Gerrits, 2001; Gerrits &

Schouten, 2004; Krebs-Lazendic & Best, 2008). These findings reflect a possible “inverse

relationship between the duration of the ISI and discrimination performance” (Werker & Tees,

1984, p.1875), especially when an AX task is used. Specifically, at a shorter ISI (500 ms or

under: Werker, 1994, p. 130), it is believed that the auditory trace of the stimulus is still available

57 In an ABX task participants decide whether X is identical to one of two acoustically different stimuli (A or B). This is

considered more cognitively demanding than an AX task because of the temporal distance between A and X (Beddor &

Gottfried, 1995, p.224). In a dual pair (4IAX) discrimination task (Beddor & Gottfried, 1995; Beddor et al., 2002) two pairs of

stimuli are given at a time, one pair containing two acoustically identical stimuli and the other containing two differing acoustic

stimuli. Pair combinations are: AB–AA, AA–BA, BB-AB and BA–BB (Gerrits & Schouten, 2004). Participants are asked to

identify which pair is different (i.e. which pair contains the differing stimuli).

58 Refer to §2.2 for a more detailed presentation of stimulus preparation procedures.

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to the listener. Thus, listeners are able to use an auditory mode of perception which makes it

easier for them to perceive contrasts which are not phonemic in nature (i.e. within-category

contrasts, Pisoni 1973). On the other hand, at a longer ISI (over 500 ms: Werker, 1994, p. 130)

the auditory trace of the stimulus is presumably no longer available in the short term memory of

the listeners. In this case, listeners are thought to use a mode of perception in which they recur to

the linguistic representations (or labels) in their long term memory. This is thought to make it

easier for listeners to discriminate contrasts to which they can assign category labels (i.e.

between-category or phonemic contrasts).

Based on our hypothesis that Diphthong and Hiatus form separate perceptual categories, we

predict that discrimination between them will be best at a longer ISI which promotes a linguistic

(Pisoni, 1973; Werker & Tees, 1984; Werker & Logan, 1985) or labeling (Gerrits & Schouten,

2004) mode of perception since this mode of perception presumably results in better between-

category distinctions59

. On the other hand, because exceptional hiatuses pattern with hiatuses on

both acoustic and articulatory measures, we hypothesize that Exceptional Hiatus and Hiatus do

not constitute separate perceptual categories. Therefore, we predict that discrimination between

Exceptional Hiatus and Hiatus will be best at a shorter ISI which promotes an auditory mode of

perception and, presumably, better within-category distinctions (Pisoni, 1973; Werker & Logan,

1985).

Finally, the study examines whether hearing these vocalic sequences within a word or in

isolation affects their perceptibility. Plomp (2002) summarizes research which suggests that

words are better candidates for “the perceptual units of speech” (p. 129) than sounds presented in

isolation. Thus, we might expect participants in the present study to perform better on the

perception task when the sequences are presented in a word vs. when they are presented in

isolation. Studies involving perception of vowels and vowel sequences have had mixed results.

For example, Face & Alvord (2004) found no difference in context (sequence within word vs.

isolated sequence) in an identification task involving Peninsular Spanish diphthongs and

exceptional hiatuses. These results mirror those of Andruski & Nearey (1992) who found that

error rates and confusion matrices were similar for vowels (monophthongs, Western Canadian

59 Refer, however to Chapter 2, §2.1.1, where it is pointed out that there is disagreement concerning the phonological status of

these sequences.

179

English speakers) when presented in isolation or in CVC syllables. Other researchers, however,

have had different results. For example, Strange et al. (1979) achieved better identification rates

for single vowels in CVC syllables than for the same vowels presented to listeners in isolation

while, more recently, Ashby (2007, using simple nonsense words rather than CVC syllables)

found the opposite to be the case (i.e. slightly worse identification rates for vowels in nonsense

words). However, these studies have generally used identification tasks. In those tasks

participants were often asked to select an appropriate label for the stimuli they heard from a fixed

set of alternatives determined a priori by the researcher. The present study aims to verify whether

discrimination of the vocalic sequences under study is affected by presentation context (word vs.

isolated sequence) when an AX discrimination task is used (i.e. with no reference to category

membership).

These hypotheses are tested in an experimental study whose methodology is outlined in §2

below. Results and accompanying statistical analyses are presented in §3 and their relevance to

the above hypotheses and previous studies is discussed in §4. A brief conclusion is given in §5.


2.1 Participants

The participants in this experiment were 6 native speakers of Mexican Spanish (AM, AN, DH,

KR, LL, MM) all of whom had already participated in the acoustic and articulatory portion of the

study (reported in Chapters 3 & 4) in previous sessions. All were naïve to the purpose of the

experiment and none had any training in linguistics or phonetics.

2.1.1 Hearing Screening

In order to be eligible for this portion of the study, participants had to have reported no history of

vision, hearing or language problems in their initial contact with the principal investigator. Since

hearing acuity may influence perceptual judgment, all participants were also required to pass a

pure tone audiometry hearing screening of the three frequencies considered to be the major

frequencies for speech: 500, 1000 and 2000 Hz (ASHA; Nittrouer, 2005, 2007). The hearing

screening was carried out at the Communications Functions Lab, Toronto Rehabilitation Centre

(Department of Speech-Language Pathology, U of T) using a GSI 61 Two Channel Clinical

Audiometer. During the procedure, the participants were seated comfortably in a sound-proof

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room and were presented sounds at the three different frequencies (pitches) and at different

intensity levels (loudness) through headphones specifically designed for the screening procedure.

The participants were instructed to give a response if they heard the sound. Typically, this

response involved raising a finger from the hand corresponding to the ear where the sound was

received. The researcher (under the supervision of Dr. Aravind Namasivayam, an audiologist and

speech-language pathologist and the lab’s Research Manager) sat in a control room adjacent to

the soundproof room and presented the sounds to the listener. A sound of a particular frequency

was presented to one ear for approximately 1 second, and its intensity was raised and lowered

until the person no longer responded consistently. Then, another signal of a different frequency

was presented to the same ear, and its intensity was varied until there was no consistent response.

This procedure was carried out for the three frequencies identified above and the other ear was

then tested in the same way. All of the above participants passed the hearing screening with a

hearing level at or below (i.e. better than) the established threshold60

. The documentation which

accompanied the hearing screening is found in Appendix 4.

2.1.2 Handedness Questionnaire

Although being right or left-handed had no consequences for experiment eligibility, a

handedness questionnaire was administered to all participants since response times on a

perceptual task may also be influenced by the handedness of the participant (Peters & Ivanoff,

1999; Barthélémy, S & Boulinguez, 2001; Dane & Erzurumluoglu, 2003). Specifically, left-

handed people may have a response time advantage since they have been found to be equally fast

in responding with both hands, while right-handed people are faster with their right hand (Peters

& Ivanoff, 1999; Dane & Erzurumluoglu, 2003). Because keyboard responses were required for

this experiment, it was deemed important to ascertain the handedness of the participants through

the use of a questionnaire. The questionnaire used here (Appendix 5) was adapted from the

Edinburgh inventory (Oldfield, 1971) and the Dutch Handedness Questionnaire (Van Strien,

1992). All the participants were right-handed.

60 The threshold level was 25dB HL (Nittrouer , 2005, 2007).

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2.2 Stimuli

The stimuli used for the perceptual study consisted of nonsense words elicited from speaker MM

following her participation in the acoustic experiment (reported in Chapter 3). As mentioned in

the Introduction, only words containing sequences with a palatal onglide [j] or high front vowel

[i] were used. These words were all of the type [piVpo], where iV represents either a diphthong

(jV), a hiatus (í.V) or follows the same patterns found in exceptional hiatuses ( ), and where V

= [a, e, o]. The use of nonsense words rather than real words in this type of experiment has the

following advantages. First, it allows the testing of the three types of sequences across the three

vowels in the same consonantal environment. This would be impossible to control with real word

tokens since minimal pairs which contrast these types of sequences do not exist in the language

(see Chapter 3, Appendix, Stimuli Table). In addition, this particular dialect of Spanish is

predicted to have few exceptional hiatuses (as discussed in Chapter 1). In fact, as we found in the

acoustic study (Chapter 3) and in the articulation study (Chapter 4) there is considerable

variation in the quantity of potential exceptional hiatuses which individual speakers of this

variety of Spanish may produce. Therefore, this type of sequence may not have surfaced reliably

in real words. Finally, using nonsense words may help avoid responses based on familiarity with

the word (Ganong, 1980; Gow et al., 2008; Clopper et al., 2010).

The audio signals were prepared for presentation in Praat (Boersma & Weenink, 2010) using a

Preprocessing script from GSU Praat Tools 1.9 (Owren, 2009), to ensure equal loudness across

all tokens in the files. One token of each sequence type was then selected for each V, based on

their showing a robust between-category distinction61

. These distinctions were determined first

auditorily by the investigator and confirmed using both temporal and frequency information from

the acoustic signal. In terms of duration, within each V category [a,e,o], the sequence types

(representing diphthongs, hiatuses and exceptional hiatuses) differed in total duration (measured

as per the criteria outlined in §2.4.1, Chapter 3 and normalized as a z-score) as well as in

duration of the Transition portion of the sequence (measured according to the criteria outlined in

§2.4.1, Chapter 3 and normalized as a proportion of the total raw duration of the sequence).

These measures of duration are summarized in Table 49.

61 The speaker who produced these words (MM) was trained by the author to make the sequence types as distinct as possible but

was not aware of the purpose of her recording these additional words.

182

Table 49. Temporal characteristics (sequence and transition duration) of nonsense word

stimuli for AX perception task

Sequence Duration Transition Duration

Type Stimulus

raw

(ms)

normalized

(z-score)

raw

(ms)

normalized

(%Transition)

Diphthong [ja] 82.35 -1.17 68.63 83.33

Hiatus [í.a] 140.51 0.62 62.24 44.30

Exceptional Hiatus [i.á] 150.71 0.93 81.52 54.09

Diphthong [je] 69.83 -1.56 59.24 84.83

Hiatus [í.e] 132.12 0.36 63.47 48.04

Exceptional Hiatus [i.é] 107.09 -0.41 44.84 41.87

Diphthong [jo] 72.88 -1.46 62.70 86.03

Hiatus [í.o] 152.96 1.00 80.40 52.56

Exceptional Hiatus [i.ó] 158.87 1.19 73.71 46.39

For all three levels of V [a,e,o], the shortest sequence was the one corresponding to the

Diphthong category (jV). Sequences corresponding to Hiatus (í.V) and Exceptional Hiatus (i.

were always longer than Diphthong in total sequence duration. Conversely, sequences

corresponding to Diphthong devoted a greater proportion of the sequence to the transition than

Hiatus and Exceptional Hiatus sequences. These patterns reflect our findings from Chapter 362

.

In addition, in most cases, the difference on both durational measures is smaller between Hiatus

and Exceptional Hiatus than between Diphthong and either Hiatus or Exceptional Hiatus (Table

50). The only exception is for the difference in %Transition where V = [e]. In this case the values

for the Diphthong-Exceptional Hiatus (D-E) difference and the Hiatus-Exceptional Hiatus (H-E)

differences are very close, although the Hiatus-Exceptional Hiatus difference is still smaller.

Table 50. Durational differences between categories of Sequence Type (normalized

measurements) for AX perception task

Differences

V Sequence duration (normalized, z-score) Transition duration (normalized, %)

D-H D-E H-E D-H D-E H-E

[a] 1.79 2.10 0.31 39.03 29.24 9.79

[e] 1.92 1.15 0.77 36.79 19.02 17.77

[o] 2.46 2.65 0.19 33.47 39.64 6.17

62 In fact, the differences between Diphthong and Hiatus in the values cited above are exaggerated (especially for transition

duration) when compared to the means of similar sequences taken from stimuli in the acoustic experiment (even those taken from

the speaker who produced the perception stimuli).

183

In terms of frequency, Figures 42-44 represent the time-normalized F1-F2 contours of the stimuli

used for each V63

. These contours suggest that differences exist between Diphthong, Hiatus and

Exceptional Hiatus, at least at some points along the contours. As we saw in Chapter 3 with

similar contours, the differences are greater for sequences where V = [a] and [o] (where both

Hiatus and Exceptional Hiatus sequences have more peripheral formant values and Diphthong

sequence have more centralized values, especially for F2, suggesting a more posterior tongue

position for diphthongs) than for sequences where V = [e] (where all Sequence Types show more

overlap for both F1 and F2).

Figure 42. Scatterplot of F1-F2 of AX perception task stimuli, by Sequence Type: V = [a]

63 Refer to Chapter 3, §2.4.2 for details of how measurements were taken and how these contours were realized.

Time

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Figure 43. Scatterplot of F1-F2 of AX perception task stimuli, by Sequence Type: V = [e]

Figure 44. Scatterplot of F1-F2 of AX perception task stimuli, by Sequence Type: V = [o]

Time

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185

However, when we further summarized the frequency data using polynomial equations and then

used the equations to carry out a Discriminant Analysis64

, we found that for all three levels of V,

Diphthong sequences were consistently correctly classified as Diphthong. On the other hand,

little distinction was made between Hiatus and Exceptional Hiatus sequences (regardless of

which combination of durational and frequency predictors were used) and these two Sequence

Types were consistently misclassified as each other but never as Diphthong. In short, the

acoustic measurements and the Discriminant Analysis of the stimuli chosen for the present

results largely match the results from Chapter 3 as well as the proposal (Hypothesis 1, this

chapter) of little difference between Hiatus and Exceptional Hiatus. Thus, we can assume, with

some degree of confidence, that the stimuli selected for the perception experiment are

representative of the Sequence Type categories under study.

After their suitability was established, the resulting 9 [iV] word tokens were subsequently

extracted from their carrier phrases at onset of initial [p] (taken at stop release) and offset of final

[o] (taken at offset of F2). The iV portions were then excised from each of these 9 word tokens.

The onset of each iV sequence was determined by an increase in F1 on the spectrogram and the

onset of periodicity on the waveform following the initial [p]. The offset of each sequence was

determined as a drop in F2 of V and the last period on the waveform before the following [p]

(Chitoran 2002, refer also to Chapter 3). All cuts were made at zero crossings. Using Adobe

Audition v1.5 software (Adobe Systems Inc., 2004), a 250ms segment of silence was then added

to the beginning and end of each (nonsense) word and sequence file as a way to avoid any

audible transient noise. The stimuli are shown in Table 51 with the sequences of interest given in

bold.

Table 51. Stimuli list for AX perception task

Sequence Type

Diphthong Hiatus Exceptional Hiatus

word sequence word sequence word sequence

[pjá.po] [ja] [pí.apo] [í.a] [pi.ápo] [i.á]

[pjé.po] [je] [pí.epo] [í.e] [pi.épo] [i.é]

[pjó.po] [jo] [pí.opo] [í.o] [pi.ópo] [i.ó]

64 Refer to Chapter 3, §3.4.1 for details on how these procedures were carried out.

186

Stimuli were organized into pairs according to sequence type (jV, í.V, or ) and vowel type [a,

e, o]. That is, each of the tokens for each vowel was paired with each of the three sequence types

for that vowel, for a total of 9 pairings per vowel type. Of the 9 pairings for each vowel type, 3

pairings involved stimuli where both members of the pair were the same (A = X) and 6 pairings

of stimuli the members of the pair were different (A≠X). To illustrate, the 9 possible pairings for

isolated sequences where V = [a] are given in (22) below:

(22) ja-ja: D_D (Diphthong_Diphthong)

ja-í.a: D_H (Diphthong_Hiatus)

ja-i.á: D_E (Diphthong_Exceptional Hiatus)

í.a-í-a: H_H (Hiatus_Hiatus)

í.a-ja: H_D (Hiatus_Diphthong)

í.a-i.á: H_E (Hiatus_Exceptional Hiatus)

i.á-i.á: E_E (Exceptional Hiatus_Exceptional Hiatus)

i.á-ja: E_D (Exceptional Hiatus_Diphthong)

i.á-í.a : E_H (Exceptional Hiatus_Hiatus)

The stimuli were arranged into four blocks separated by Stimulus type (Word vs. Sequence) and

by ISI in ms (500 vs. 1000). These ISIs were selected in order to promote an auditory mode of

discrimination (ISI = 500 ms) and a ‘linguistic’ (Pisoni, 1973; Werker & Tees, 1984; Werker &

Logan, 1985) or ‘labeling’ (Gerrits & Schouten, 2004) mode of discrimination (ISI = 1000 ms).

The durations are based on findings reported in Werker (1994, p. 130) and in Krebs-Lazendic &

Best (2008, p. 291).

Each block consisted of 27 trials corresponding to 3 vowels ([a], [e] and [o]) X 9 pair types (see

above). The order of the blocks was fixed as follows: (i) Word at 500 ISI, (ii) Word at 1000 ISI,

(iii) Sequence at 500 ISI, and (iv) Sequence at 1000 ISI. The order of trials within the blocks,

however, was randomized for each listener. Thus, each listener heard a total of 108 pairs of

perceptual stimuli (27 pairs X 2 stimulus types X 2 ISI)65

. Prior to the test session, each listener

participated in a practice session consisting of 24 trials (6 pairs X 2 stimulus types X 2 ISI)

meant to familiarize them with the stimuli and the task.

65 Participants also heard the same number of stimuli produced by speakers of two other Spanish varieties, Argentine and

Peninsular (presented in separate blocks). Only the results for their performance on the Mexican Spanish (i.e. the native variety)

stimuli are presented here.

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2.3 Tasks and procedures

Following the administration of the handedness questionnaire and hearing screening, the

participants proceeded to the perceptual testing. As with the previous two experiments, the

participants were tested individually. The perception experiment took place in the same lab

(Communications Functions Lab) where the participants took the handedness questionnaire and

hearing screening, on the same day as these screening procedures.

For the experiment, the listeners were seated in a sound-proof booth in front of a computer

keyboard placed on a flat surface with the left and right Shift keys marked with a green dot

(symbolizing I for Igual = same) and a red dot (symbolizing D for Diferente = different). The

green and red dots also appeared on the computer screen in front of the participants with the

words Igual and Diferente underneath the corresponding dot. In order to account for the

observation that the listener’s preferred hand is generally faster to respond (Peters & Ivanoff

1999; Dane & Erzurumluoglu, 2003), the shift key on which red (different) or green (same)

appeared was counterbalanced across listeners.66

The task employed was an AX discrimination task (e.g. Beddor & Gottfried, 1995) where

listeners hear pairs of stimuli where each stimulus pair consists of a reference stimulus (A) and a

test stimulus (X) and decide if they are the same or different. The AX task in the present

experiment was administered as follows. The listeners first heard the reference stimulus and then

the test stimulus. Following this, the listeners decided whether the two stimuli were the same or

different by pressing on the appropriate key on a computer keyboard. The participants were

instructed to press the green key if they thought the two words or sequences in the pair they

heard were pronounced the same and to press the red key if they thought their pronunciation was

different. They then proceeded to the familiarization (training) trials.

During this training phase, the participants received feedback on their responses. The feedback

consisted of a yellow X which appeared on the computer screen in front of them (between the

green and red dots) if they made an incorrect choice. Whenever the yellow X appeared, the

66 Because listeners from other dialects groups were also tested during the same period (those results are not reported in this

chapter) two of the Mexican participants (AN and DH) had the red (different) key on the left and the green (same) key on the

right. The remaining Mexican listeners received the opposite ordering of the keys (green-same key on left and red-different key

on right).

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participants then had to press the correct key in order to proceed to the following trial. Following

the familiarization trials, the listeners were given an opportunity to ask questions or review the

task instructions with the investigator. No feedback was given during the experimental phase.

For both training and experimental phases the auditory stimuli were presented at 10dB above HL

(adjusted according to listener, typically 45dB HL to the right ear and 35 dB HL to the left ear)

via free field speakers placed at 45 azimuth to the listener. The speakers were connected to the

GSI 61 audiometer which in turn was connected to a small laptop computer in the control booth.

The computer used DirectRT presentation software (Empirisoft Corp.) to randomize and present

the stimuli. There was a brief break given between each block to avoid fatiguing the listener. The

researcher advanced the next block as soon as the listener indicated she was ready to proceed.

Within each block, participants were not given a time limit within which to make their responses

although they were instructed to respond as quickly as they could. Following each key press

response by the listener, the next trial advanced automatically with a 1000ms interval between

stimuli pair. Discrimination responses as well as response times (RT) were recorded by the

Direct RT software and exported to an EXCEL file for analysis67

. A total of 540 tokens (108 x 5

participants) were collected and are analyzed here68

.

2.4 Analysis

In the present experiment, the number of participants as well as the number of observations

collected from each participant was rather small. In addition, some of the data (in particular for

Pair Type) were not normally distributed. For these reasons, responses were analyzed using

nonparametric discrimination measures. These, in turn were evaluated using nonparametric

statistical tests.

67 Only discrimination responses are reported here.

68 The 108 tokens collected for participant MM (the participant who produced the experiment stimuli) were not included in the

analysis. Although her responses did not differ much from those of the other participants on the accuracy and sensitivity

measures, they differed in regards to response bias. Specifically, she showed a consistently greater liberal bias (i.e. a greater

tendency to respond Different on A≠X pairs) than the others. These differences were enough to affect the results of the statistical

tests with her inclusion. She also exhibited differences with regards to RTs (hers were generally longer than those of the

remaining participants, especially for incorrect responses). However, as pointed out above, the RT data is not analyzed here.

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2.4.1 Discrimination Measures

Discrimination responses were analyzed in terms of response accuracy, response sensitivity and

response bias. All these measures required that the participant’s correct and incorrect responses

be tabulated and further categorized as illustrated in Table 52 (adapted for AX task from

Macmillan & Creelman, 2005, p.4).

Table 52. Categorization of correct and incorrect responses for AX perception tasks

RESPONSE

DIFFERENT SAME

STIMULUS DIFFERENT HITS (H) MISSES (M)

SAME FALSE ALARMS (F) CORRECT REJECTIONS (CR)

Thus, correct responses are divided into two categories: HITS (H = where A and X are different

and the listener correctly responds Different) and CORRECT REJECTIONS (CR = where A and

X are the same and the listener correctly responds Same, thus rejects that they are different).

Similarly, incorrect responses are divided into two categories: MISSES (M = where A and X are

different but the listener responds Same) and FALSE ALARMS (F = where A and X are the

same but the listener responds Different, thus reporting a difference where there was none).

Table 53 shows the total number of each response type across all participants as well as for each

individual participant across all conditions.

Table 53. Summary of AX perception task responses, by Response type and Participant

across all conditions

Participant

Response type

Total N(trials)

Correct Incorrect

CR H F M

AM 34 30 2 42 108

AN 36 45 0 27 108

DH 32 41 4 31 108

KR 35 54 1 18 108

LL 36 49 0 23 108

OVERALL 173 219 7 141 540

2.4.1.1 Response Accuracy: proportion correct, p(c)

The first discrimination measure reported is the proportion of correct responses or p(c). This

measure reflects listener accuracy at discriminating between pairs of Same and Different stimuli.

It is calculated from the number of correct responses out of the total number (N) of

responses/trials for each condition tested. Recall from above that correct responses fall into two

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categories: HITS (H) and CORRECT REJECTIONS (CR). The proportion of correct responses

was calculated from the raw count data, according to the following formula:

(23) p(c) = (H + CR)/ N (Macmillan & Creelman, 2005, p. 7)

In Figure 45, the raw data in the above table has been converted to proportions (reported as

percentages) by dividing by the row total N. These figures show that, overall, correct responses

(CR + H) make up the greatest proportion of total responses (N), with a mean of 0.73 (rounded to

two decimal points), representing slightly less than three quarters of the responses.

40.6%Hit

32.0%Correct Rejection

26.1%Miss

1.3%False Alarm

Figure 45. Pie chart of AX perception task responses (%) by Response Type, across all

conditions

The same pattern is seen in individual responses (Figure 46), with all the participants showing a

greater than chance proportion of correct responses. Thus, at first glance it would appear that the

participants are making the appropriate discriminations in the stimuli pairs and are not merely

guessing in their response. On the other hand, individual variation in the responses is also

already apparent. In particular, when we look only at the proportion of correct responses (Hits +

Correct Rejections together), we find that participant AM’s performance is worse than that of the

other four participants, with a proportion of correct responses of only 0.59 (Table 54). Thus, not

all the participants may be discriminating to the same degree.

Correct Responses = 73%

191

Pe

rce

nt

Re

sp

on

se

(%

)

Participant LLKRDHANAM

100

80

60

40

20

0

Response Type

False Alarm

Miss

Correct Rejection

Hit

Figure 46. Bar chart of AX perception task responses (%) by Response Type and

Participant, across all conditions

The measure of proportion correct responses, p(c) is an inherently nonparametric measure

(Macmillan & Creelman 2005: 117), making it suitable for the small amount of data in the

present experiment. However, it does not take response bias into account. In other words, p(c)

may vary according to the listener’s tendency to answer either Different or Same. As such, the

p(c) scores reflect the participants’ response to a combination of the signal + noise. To account

for possible bias, listener responses were also used to calculate response sensitivity (signal only)

and, separately, response bias (noise only).

2.4.1.2 Response Sensitivity: A'

Here we calculated A', a nonparametric measure of perceptual sensitivity (Grier, 1971; Johnson,

1976; Aaronson & Watts, 1987) which is separate from response bias. This measure is used in

lieu of d' in cases where the normal distribution and equal-variances assumptions of d' cannot be

met (Donaldson, 1992; Stanislaw & Todorov, 1999) and/or when only small amounts of data are

available for analysis (Werker & Tees, 1984; Goldinger, 1998). Prior to calculating A′ the HIT

(H) and FALSE ALARM (F) rates were calculated as follows (from Macmillan & Creelman,

2005, p. 19):

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(24) HIT and FALSE ALARM rate formulas

(a) H (Hit Rate) = Hits/Hits + Misses

(b) F (False Alarm Rate) = False Alarms/False Alarms+ Correct Rejections

As an example, using the data from Table 52 in the above formulas we find that the overall H

and F rates (rounded to two decimals) are as follows:

(i) H = 219/219+141 = 0.61

(ii) F = 7/7+173 = 0.04

Where necessary, H and F proportions were adjusted to avoid values of 1 or 0 with the following

transformations (from Macmillan & Creelman, 2005, p. 19):

(25) H and F transformations

(a) for H = 1: Hits-0.5/Hits + Misses

(b) for F = 0: 0.5/ False Alarms+ Correct Rejections

An example from the data in Table 52 illustrates how these transformations were applied.

Participant AN, for instance, had 36 Correct Rejections and 0 False Alarms; applying the

formula in (25) (ii) above gives her an F rate of 0.5/36 = 0.01.

The H and F rates were then used to calculate A′ according to the following formula (from

Stanislaw & Todorov 1999: 142) which combines the two separate formulas often cited for H≥F

and for H< F (as in Snodgrass & Corwin, 1988).

(26) A′ = , where: sign (H-F) = 1 when H>F,0 when

H = F,and-1 when H<F; max (H, F)

corresponds to the greater of H or F

The full range for A′ is from 0 to 1. However, the practical range for this measure is between 0.5

(indicating chance performance and interpreted as an inability on the part of the listener to detect

differences between A and X, i.e. H = F) and 1 (indicating perfect performance). Values below

0.5 may arise as a result of “sampling error or response confusion” (Stanislaw & Todorov, 1999,

p. 140). Thus, the higher the value of A′ obtained, the greater the degree of sensitivity to a

difference between A and X is assumed to be.

2.4.1.3 Response Bias: β″D

Bias measures are based on the assumption that in this type of discrimination task, the decision-

making process employed by participants depends on two factors. The first is sensitivity to the

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stimulus characteristics which we measured using A′. The second factor is bias, which reflects

the participants’ response preference rather than any relevant information contained in the

stimulus. That is, each participant makes a personal decision regarding whether it is better to

maximize H and CR or to minimize F and M (Macmillan & Creelman, 2005, p. 37-39). In an AX

discrimination task, for example, each participant may divide the stimulus axis into Same and

Different regions at a different point or criterion (Macmillan & Creelman, 2005). What the bias

measure tells us then is whether the participant is more likely to respond Same or to respond

Different for a particular condition. The measure of response bias used here is β″D. This measure,

rather than the more common β″, was used because of its greater independence from A′

(Donaldson, 1992). It was calculated according to the following formula (adapted from

Donaldson, 1992, p. 276)

(27) β″D = [(1-H) (1-F)-HF]/[(1-H)(1-F)+HF]

In addition to reflecting personal preference for Same or Different responses, the β″D value is of

interest because it can vary from condition to condition. For example, increased familiarity with

a task (a practice effect) may change the value of β″D, independently of sensitivity changes. The

values for β″D range from -1 to 1. A value of 0 is interpreted as having no bias while positive

values are interpreted as a bias toward responding Same (a conservative bias) and negative

values as a bias toward responding Different (a liberal bias).

The results for p(c), A' and β″D scores across all conditions are summarized in Table 54.

Table 54. Summary of response accuracy (p(c)), sensitivity (A') and bias (β″D) scores by

Participant, across all conditions

Participant p(c) A′ β″D

AM 0.59 0.81 0.92

AN 0.75 0.90 0.95

DH 0.68 0.83 0.72

KR 0.82 0.93 0.84

LL 0.79 0.91 0.94

OVERALL

Mean = 0.73 Mean = 0.88 Mean = 0.87

Median = 0.75 Median = 0.90 Median = 0.92

SD = 0.092 SD = 0.053 SD = 0.096

A graphic expression of the mean p(c), A' and β″D scores across all conditions (Figure 47)

illustrates how these measures can give different insights. For example, it is obvious that all the

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participants had a rather large conservative bias toward Same responses, as reflected in the

positive β″D scores. In addition, we see that removing this bias (i.e. the noise) from the p(c)

scores reduces response variability (as reflected in the smaller standard deviations in the A' score

results).

1.0

0.8

0.6

0.4

0.2

0.0

1.0

0.8

0.6

0.4

0.2

0.0

1.0

0.5

0.0

-0.5

-1.0

p(c) A' ß?D


Figure 47. Bar chart of mean p(c), A' and β″D scores, across all conditions

Looking at the results for each participant further illustrates how p(c) and A' measures can differ.

In Table 54, for example, we see that participants AM and DH have very similar scores on A'

(0.81 and 0.83 respectively). Presumably, then, their performance on the discrimination task was

approximately the same. In other words, AM and DH did worse than the other three participants,

all of whom had A' scores of 0.90 or higher. On the other hand, on the measure of p(c), AM and

DH had scores which were further apart (0.59 and 0.68, respectively), giving the impression that

DH did better than AM on the discrimination task. The results for these two participants also

highlight the independence of A' and β″D. For example, AM clearly has a more extreme Same

bias (β″D = 0.92) than DH (β″D = 0.72), even though both scored similarly on sensitivity.

Because there were more Different trials than Same trials in the experiment, DH’s less extreme

Same bias resulted in higher p(c) scores than AM even though their sensitivity (A′) scores were

similar. Thus, eliminating bias from a response can affect its interpretation.

B”D

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2.4.2 Statistical Analysis

After computing the p(c), A′ and β″D scores, the Friedman Test statistic was used to determine if

any differences between levels of the variables tested were statistically significant (as opposed to

being attributable to chance and/or bias). The Friedman Test Statistic is the nonparametric

equivalent to the repeated-measures ANOVA procedures (Corder & Foreman, 2009, p. 80) used

in Chapters 3 and 4. As in Chapters 3 and 4, these tests were performed on the statistical program

MINITAB 14 (Minitab Inc.), with p level set at .05. In all cases, the test statistic adjusted for ties

is reported. Where appropriate, the Wilcoxon Signed Ranks test was used as a post-hoc test

(Corder & Foreman, 2009, p. 87). When multiple comparisons were conducted, a Bonferroni

procedure was used to correct α for Type I error rate (from Corder & Foreman, 2009, p. 81):

(28) , Where = adjusted α level, α = original α level of 0.05 and k =

number of comparisons

3 Results

For this chapter, the results are organized according to the hypothesis being tested. In §3.1 the

focus is on Hypothesis 1 as we examine the effects of Pair Type (D_D, D_E, D_H, E_D, E_E,

E_H, H_D, H_E, or H_H). In §3.2, we concentrate on Hypothesis 2 and examine the effects of

the non-high vowel (V) in the sequence ([a], [e] or [o]). Within these two sections, we also

examine any differences in discrimination at the level of the individual listeners (Hypothesis 3).

3.1 Hypothesis 1: Pair Type Effects

Here we test the prediction that discrimination is better between pairs with Diphthong and Hiatus

than between pairs consisting of Hiatus and Exceptional Hiatus. The discrimination measures we

are concerned with then are those for pairs where A≠X since we are interested in measuring

sensitivity to differences. Pairs where A = X should (in theory) show no sensitivity and thus have

a p(c) value of 1.00, an A′ value of 0.5 and a β″D value of 1.00. As shown in Table 55, however,

these ideal values for A = X pairs were achieved only for Diphthong-Diphthong (D_D) pairs.

The values for Exceptional Hiatus-Exceptional Hiatus (E_E) and Hiatus-Hiatus (H_H) pairs

deviate from the expected values for some participants (AM and DH for both E_E and H_H

pairs; KR for E_E pairs only), possibly due to “response confusion” (Stanislaw & Todorov,

1999).

196

Table 55. Summary of p(c), A′ and β″D scores for Pair Type (A = X)

Summary of p(c), A′ and β″D scores for Pair Type (A = X)

Pair Type

Participant D_D E_E H_H

p(c)

AM 1.00 0.92 0.92

AN 1.00 1.00 1.00

DH 1.00 0.75 0.92

KR 1.00 0.92 1.00

LL 1.00 1.00 1.00

OVERALL

Mean = 1.00 Mean = 0.92 Mean = 0.97


SD = 0.000 SD = 0.102 SD = 0.044

A′

AM 0.50 0.36 0.36

AN 0.50 0.50 0.50

DH 0.50 0.24 0.36

KR 0.50 0.36 0.50

LL 0.50 0.50 0.50

OVERALL

Mean = 0.50 Mean = 0.39 Mean = 0.44


SD = 0.000 SD = 0.110 SD = 0.077

β″D

AM 1.00 0.99 0.99

AN 1.00 1.00 1.00

DH 1.00 0.97 0.99

KR 1.00 0.99 1.00

LL 1.00 1.00 1.00

OVERALL

Mean = 1.00 Mean = 0.99 Mean = 1.00


SD = 0.000 SD = 0.012 SD = 0.005

Despite these deviations from the expected values, there are no statistically significant

differences between these pairs and Friedman Test results for Pair Type (A = X) are the same for

p(c), A′ and β″D: S69

= 5.00, df = 2, p = 0.082.

The results for the A≠X pairs are illustrated in Figure 48. A first glance suggests that pairs

consisting of Exceptional Hiatus and Hiatus (E_H and H_E) were among those with the lowest

discrimination scores and highest bias scores for all participants. This would seem to support the

prediction that vowel sequences forming a Hiatus are difficult to distinguish from those whose

69 Minitab refers to the Friedman Test statistic (FR, Corder & Foreman, 2009) as S. Because the test uses a chi-square

distribution, it is sometimes also referred to as χ2 in other statistical programs (e.g. SPSS/PAWS).

197

pattern resembles an Exceptional Hiatus. However, this support is challenged by the observation

that the lowest discrimination scores were achieved with H_D pairs.

H_EH_DE_HE_DD_HD_E

1.0

0.8

0.6

0.4

0.2

0.0H_EH_DE_HE_DD_HD_E

1.0

0.8

0.6

0.4

0.2


1.0

0.5

0.0

-0.5

-1.0

p(c) A' ß?D


Figure 48. Bar chart of mean p(c), A' and β″D scores for Pair Type (A≠X)

In fact, the Friedman Test results for this data (Table 56) show that, contrary to our predictions,

pairs where A≠X do not differ significantly from each other. Overall then, it does not appear to

be any easier to discriminate between Diphthong and Hiatus than it does between Hiatus and

Exceptional Hiatus. Nor is there any significant difference in response bias between the pairs

either.

Table 56. Summary of p(c), A′ and β″D scores for Pair Type (A≠X)

Pair Type

Participant D_E D_H E_D E_H H_D H_E

p(c)

AM 0.25 0.58 0.50 0.50 0.42 0.25

AN 0.83 0.67 0.75 0.58 0.42 0.50

DH 0.58 0.75 0.50 0.50 0.33 0.75

KR 0.75 0.83 0.92 0.58 0.92 0.50

LL 0.83 0.67 0.92 0.58 0.33 0.75

OVERALL

Mean=0.65 Mean=0.70 Mean=0.72 Mean=0.55 Mean=0.48 Mean=0.55

Med.= 0.75 Med.= 0.67 Med.= 0.75 Med = 0.58 Med=0.42 Med.= 0.50

SD = 0.245 SD= 0.094 SD = 0.211 SD = 0.044 SD=0.248 SD=0.209

Friedman Test: S = 7.38, df = 5, p = 0.194

B”D

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Table 56 (cont’d)

A′

AM 0.76 0.87 0.85 0.85 0.82 0.76

AN 0.94 0.90 0.92 0.87 0.82 0.85

DH 0.87 0.92 0.85 0.85 0.79 0.92

KR 0.92 0.94 0.97 0.87 0.97 0.85

LL 0.94 0.90 0.97 0.87 0.79 0.92

OVERALL


Med.=0.92 Med.=0.90 Med.=0.92 Med.=0.87 Med.=0.82 Med.=0.85

SD=0.076 SD=0.026 SD=0.060 SD=0.011 SD=0.075 SD=0.066


β″D

AM 0.97 0.89 0.92 0.92 0.94 0.97

AN 0.64 0.84 0.77 0.89 0.94 0.92

DH 0.89 0.77 0.92 0.92 0.96 0.77

KR 0.77 0.64 0.35 0.89 0.35 0.92

LL 0.64 0.84 0.35 0.89 0.96 0.77

OVERALL


Med.=0.77 Med.=0.84 Med.=0.77 Med.=0.89 Med.=0.94 Med.=0.92

SD=0.148 SD=0.097 SD=0.291 SD=0.016 SD=0.269 SD=0.094


Of note among these different pairs, however, is the amount of individual variation shown in

Table 56. For example, participant AM had lower p(c) values than the other participants on

almost all the A≠X pairs. Since AM’s performance on the A = X pairs was close to or equal to

the group performance, her low p(c) scores on the different pairs might be taken as an indication

that she cannot reliably discriminate differences between Diphthong and Hiatus or between

Hiatus and Exceptional Hiatus. In fact, in the previous two chapters, AM was identified as being

among the participants who had the smallest Diphthong-Hiatus differences and who contributed

the most misclassified sequences (i.e. Exceptional Hiatuses) on both acoustic and articulatory

measures. On the other hand, her A′ and β″D scores suggest that her poor performance is an

indication of a response bias (i.e. she has a strong bias toward responding Same, a strategy which

is successful only with pairs where A = X).

An additional observation regards the possibility of a stimulus ordering effect on response

accuracy (e.g. Cowan & Morse, 1986 for vowel order; Francis & Ciocca, 2003 for tone order) on

these A≠X pairs. Thus, although there are no significant differences found between any of the

pairs, there appears to be a slight ordering effect with pairs of Diphthong (D) and Hiatus (H).

Specifically, it looks as though overall listeners were more likely to respond accurately (i.e. to

notice a difference) when D was presented before H than when H was presented before D. In

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fact, 4 of the 5 participants had lower p(c) and A′ values and higher β″D values for H_D pairs

than for D_H pairs, with participant KR being the only exception.

Another interesting pattern of note in the above results is that the participants generally have

higher p(c) and A′ scores with E_D (Exceptional Hiatus-Diphthong) pairs than with H_D

(Hiatus-Diphthong) pairs. Once again, KR is the only exception. The difference between E_D

and H_D is especially large for participant LL. These differences are unexpected if we consider

only how Hiatus and Exceptional Hiatus differ from Diphthong in terms of duration and

frequency parameters. That is, given that Hiatus and Exceptional Hiatus are closer to each other

on these parameters than they are to Diphthong, we might expect them to behave similarly in

pairs with Diphthong. These two patterns suggest that there may be other factors influencing the

results for Pair Type. We consider next whether ISI (500 vs. 1000) and/or Stimulus Type (Word

vs. Sequence) can explain these patterns.

3.1.1 Stimulus Type and ISI Effects on Pair Type

On its own, Stimulus Type (Word vs. Sequence) had little effect on discrimination (Table 57).

Participants performed only slightly better (i.e. had higher accuracy and sensitivity scores and

had lower bias scores) when stimuli were presented within a nonsense word (Word condition)

than when they were presented in isolation (Sequence condition). While this slight advantage of

the Word condition is as predicted, the differences are not significant for any of the measures.

However, it is possible that any significant differences between Sequence and Word conditions

may have been attenuated by practice effects. Recall from §2.2 that all the participants heard the

stimuli first in the Word condition and then the Sequence condition. Thus, the experience the

participants acquired with the stimuli characteristics in the Word condition may have resulted in

an improved performance in the Sequence condition which followed. This in turn may have

reduced any advantage of the Word condition. Individual variation is also evident and, again,

AM stands out. For example, she had the lowest values for p(c) and A' for both Word and

Sequence conditions. Although AM’s p(c) score increases in the Sequence condition, this effect

is due to a decrease in bias rather than an increase in sensitivity since she has similar A' values

for both levels of this factor but a smaller β″D score for the Sequence condition. This decrease in

bias likely reflects a practice effect, as pointed out above.

200

In a similar vein, all the participants seemed to perform better when stimuli were presented with

an ISI of 1000 ms than with the shorter ISI of 500 ms (Table 57). This difference, although

small, was found to be statistically significant for p(c) and A′. Response bias, on the other hand,

remained constant (even though AM and KR showed increases in bias at the 1000 ISI condition).

Still, since all the participants received the stimuli at 500 ISI before those at 1000 ISI, the

increases in response accuracy and sensitivity are also likely attributable to a practice effect.

Table 57. Summary of p(c), A′ and β″D scores for Stimulus Type (Sequence vs. Word) and

ISI (500 vs. 1000)

Stimulus Type ISI

Participant Word Sequence 500 1000

p(c)

AM 0.54 0.65 0.57 0.61

AN 0.78 0.72 0.74 0.76

DH 0.74 0.61 0.65 0.70

KR 0.83 0.81 0.78 0.87

LL 0.83 0.74 0.78 0.80

OVERALL

Mean = 0.74 Mean = 0.71 Mean = 0.70 Mean = 0.75

Median = 0.78 Median = 0.72 Median = 0.74 Median = 0.76

SD = 0.120 SD = 0.078 SD = 0.092 SD = 0.099

S = 1.80, df = 1, p = 0.180 S = 5.00, df = 1, p = 0.025

A′

AM 0.80 0.81 0.77 0.83

AN 0.90 0.88 0.89 0.90

DH 0.86 0.79 0.81 0.85

KR 0.92 0.92 0.90 0.94

LL 0.93 0.89 0.90 0.91

OVERALL



SD = 0.053 SD = 0.055 SD = 0.060 SD = 0.045

S = 1.00 , df = 1, p = 0.317 S = 5.00, df = 1, p = 0.025

β″D

AM 0.98 0.75 0.84 0.96

AN 0.89 0.92 0.91 0.90

DH 0.60 0.80 0.75 0.67

KR 0.66 0.86 0.76 0.79

LL 0.84 0.91 0.89 0.88

OVERALL



SD = 0.159 SD = 0.073 SD = 0.073 SD = 0.113

S = 1.80 , df = 1, p = 0.180 S = 0.20 , df = 1, p = 0.655

When Stimulus Type and ISI are considered in combination with each other, the only statistically

significant result is for A′ (S = 9.73, df = 3, p = 0.021). This occurs because the overall sensitivity

score of the group is worst for the Word condition at 1000 ISI while the other three conditions

201

(Word at 500 ISI, Sequence at 500 ISI and Sequence at 1000 ISI) had comparable values for A′.

However, none of the post-hoc Wilcoxon Signed Rank Tests were significant at the new α of

0.05/3 = 0.02. In fact, in each comparison, the obtained value was p = 0.059.

When we look at the effects of Stimulus Type and ISI in combination with Pair Type (Table 58)

we fail to find any significant effects. Despite this, we do note that some combinations yield

higher accuracy and sensitivity scores and/or lower bias scores than others. For example, the

ordering effect observed earlier between D_H (Diphthong-Hiatus) pairs and H_D (Hiatus-

Diphthong) pairs is now most obvious for Stimulus Type = Word and ISI = 1000. Within this

specific combination of Pair Type, Stimulus Type and ISI we observe that pairs where the

Diphthong is heard first (D_H) have higher discrimination scores (both p(c) and A′) and lower

bias scores (β″D) than pairs where the Hiatus is heard first (H_D). In addition, the H_D pairs

consistently have greater variability, as is evident in larger standard deviations. Similarly, the

difference also observed earlier between E_D (Exceptional Hiatus-Diphthong) pairs and H_D

(Hiatus-Diphthong) pairs is also greatest for Stimulus Type = Word and ISI = 1000. Specifically,

E_D pairs have higher discrimination scores and lower bias scores than D_H pairs. The E_D

pairs also have less variable scores (i.e. smaller standard deviations).

202

Table 58. Summary of p(c), A′ and β″D scores for Pair Type (A≠X), by Stimulus Type

(Word vs. Sequence) and ISI (500 vs. 1000), across Participants

Word Sequence

ISI Pair Type Mean Median SD Mean Median SD

p(c)

500

D_E 0.73 0.67 0.280 0.53 0.67 0.381

D_H 0.67 0.67 0.237 0.60 0.67 0.281

E_D 0.73 0.67 0.280 0.54 0.67 0.300

E_H 0.60 0.67 0.152 0.47 0.33 0.186

H_D 0.60 0.67 0.281 0.40 0.33 0.152

H_E 0.53 0.33 0.300 0.60 0.67 0.152

1000

D_E 0.67 0.67 0.408 0.67 0.67 0.000

D_H 0.74 0.67 0.148 0.80 0.67 0.181

E_D 0.80 1.00 0.299 0.80 0.67 0.181

E_H 0.60 0.67 0.281 0.54 0.67 0.300

H_D 0.40 0.33 0.435 0.53 0.67 0.381

H_E 0.53 0.33 0.448 0.54 0.67 0.300

Friedman Test: S = 24.58 , df = 23 , p = 0.373

A′

500

D_E 0.83 0.84 0.090 0.69 0.84 0.283

D_H 0.82 0.84 0.083 0.79 0.84 0.102

E_D 0.83 0.84 0.090 0.71 0.84 0.282

E_H 0.81 0.84 0.072 0.74 0.68 0.088

H_D 0.79 0.84 0.102 0.71 0.68 0.072

H_E 0.76 0.68 0.106 0.81 0.84 0.072

1000

D_E 0.74 0.84 0.297 0.84 0.84 0.000

D_H 0.85 0.84 0.027 0.86 0.84 0.033

E_D 0.84 0.90 0.095 0.86 0.84 0.033

E_H 0.79 0.84 0.102 0.71 0.84 0.282

H_D 0.57 0.68 0.337 0.69 0.84 0.283

H_E 0.67 0.68 0.282 0.71 0.84 0.282


β″D

500

D_E 0.34 0.43 0.346 0.54 0.43 0.389

D_H 0.42 0.43 0.290 0.50 0.43 0.341

E_D 0.34 0.43 0.346 0.54 0.43 0.255

E_H 0.51 0.43 0.174 0.66 0.82 0.214

H_D 0.50 0.43 0.341 0.74 0.82 0.174

H_E 0.58 0.82 0.365 0.51 0.43 0.174

1000

D_E 0.37 0.43 0.412 0.43 0.43 0.000

D_H 0.34 0.43 0.192 0.26 0.43 0.236

E_D 0.25 0.00 0.369 0.26 0.43 0.236

E_H 0.50 0.43 0.341 0.54 0.43 0.255

H_D 0.65 0.82 0.432 0.54 0.43 0.389

H_E 0.53 0.82 0.488 0.54 0.43 0.255


203

When we look at the individual results (Table 59), we see that three of the five participants (AM,

DH and LL) are responsible for the differences between D_H and H_D pairs (for Word at 1000

ISI). Similarly, Participants DH and LL are behind the differences between E_D pairs and H_D

pairs.

Table 59. Summary of p(c), A′ and β″D scores for Pair Type (A≠X), by Stimulus Type

(Sequence vs. Word) and ISI (500 vs. 1000), by Participant

Word

Pair Type

ISI Participant D_E D_H E_D E_H H_D H_E

p(c)

500

AM 0.33 0.33 0.33 0.33 0.33 0.33

AN 1.00 0.67 0.67 0.67 0.67 0.33

DH 0.67 0.67 0.67 0.67 0.33 1.00

KR 0.67 1.00 1.00 0.67 1.00 0.33

LL 1.00 0.67 1.00 0.67 0.67 0.67

1000

AM 0.00 0.67 0.33 0.33 0.33 0.00

AN 0.67 0.67 1.00 0.67 0.67 0.33

DH 0.67 0.67 0.67 1.00 0.00 1.00

KR 1.00 1.00 1.00 0.33 1.00 0.33

LL 1.00 0.67 1.00 0.67 0.00 1.00

A′

500

AM 0.68 0.68 0.68 0.68 0.68 0.68

AN 0.90 0.84 0.84 0.84 0.84 0.68

DH 0.84 0.84 0.84 0.84 0.68 0.90

KR 0.84 0.90 0.90 0.84 0.90 0.68

LL 0.90 0.84 0.90 0.84 0.84 0.84

1000

AM 0.21 0.84 0.68 0.68 0.68 0.21

AN 0.84 0.84 0.90 0.84 0.84 0.68

DH 0.84 0.84 0.84 0.90 0.21 0.90

KR 0.90 0.90 0.90 0.68 0.90 0.68

LL 0.90 0.84 0.90 0.84 0.21 0.90

β″D

500

AM 0.82 0.82 0.82 0.82 0.82 0.82

AN 0.00 0.43 0.43 0.43 0.43 0.82

DH 0.43 0.43 0.43 0.43 0.82 0.00

KR 0.43 0.00 0.00 0.43 0.00 0.82

LL 0.00 0.43 0.00 0.43 0.43 0.43

1000

AM 1.00 0.43 0.82 0.82 0.82 1.00

AN 0.43 0.43 0.00 0.43 0.43 0.82

DH 0.43 0.43 0.43 0.00 1.00 0.00

KR 0.00 0.00 0.00 0.82 0.00 0.82

LL 0.00 0.43 0.00 0.43 1.00 0.00

204

Table 59 (cont’d)

Sequence

Pair Type

ISI Participant D_E D_H E_D E_H H_D H_E

p(c)

500

AM 0.00 0.67 0.67 0.67 0.33 0.67

AN 1.00 0.33 0.67 0.33 0.33 0.67

DH 0.33 1.00 0.00 0.33 0.33 0.33

KR 0.67 0.33 0.67 0.67 0.67 0.67

LL 0.67 0.67 0.67 0.33 0.33 0.67

1000

AM 0.67 0.67 0.67 0.67 0.67 0.00

AN 0.67 1.00 0.67 0.67 0.00 0.67

DH 0.67 0.67 0.67 0.00 0.67 0.67

KR 0.67 1.00 1.00 0.67 1.00 0.67

LL 0.67 0.67 1.00 0.67 0.33 0.67

A′

500

AM 0.67 0.84 0.84 0.84 0.68 0.67

AN 0.90 0.68 0.84 0.68 0.68 0.67

DH 0.68 0.90 0.21 0.68 0.68 0.33

KR 0.84 0.68 0.84 0.84 0.84 0.67

LL 0.84 0.84 0.84 0.68 0.68 0.67

1000

AM 0.84 0.84 0.84 0.84 0.84 0.21

AN 0.84 0.90 0.84 0.84 0.21 0.84

DH 0.84 0.84 0.84 0.21 0.84 0.84

KR 0.84 0.90 0.90 0.84 0.90 0.84

LL 0.84 0.84 0.90 0.84 0.68 0.84

β″D

500

AM 0.84 0.43 0.43 0.43 0.82 0.43

AN 0.00 0.82 0.43 0.82 0.82 0.43

DH 0.82 0.00 1.00 0.82 0.82 0.82

KR 0.43 0.82 0.43 0.43 0.43 0.43

LL 0.43 0.43 0.43 0.82 0.82 0.43

1000

AM 0.43 0.43 0.43 0.43 0.43 1.00

AN 0.43 0.00 0.43 0.43 1.00 0.43

DH 0.43 0.43 0.43 1.00 0.43 0.43

KR 0.43 0.00 0.00 0.43 0.00 0.43

LL 0.43 0.43 0.00 0.43 0.82 0.43

In summary, on all measures we fail to show that discrimination between Diphthong and Hiatus

is better than discrimination between Exceptional Hiatus and Hiatus. We also fail to show that

discrimination between Diphthong and Hiatus is best at the longer ISI while discrimination

between Exceptional Hiatus and Hiatus is best at the shorter ISI. In addition, we find no

statistical difference between Word and Sequence presentations. Despite these statistically nil

results, we do observe some interesting patterns in the data. Specifically, we notice a possible

stimulus ordering effect stimuli pairs consisting of Diphthong (D) and Hiatus (H). A related

205

observation is that participants generally achieved higher discrimination scores with Exceptional

Hiatus-Diphthong (E_D) pairs than with Hiatus-Diphthong (H_D) pairs. A possible explanation

for these patterns is discussed in §4 (Summary and Discussion).

In terms of individual variation, we see that some participants consistently do worse than others.

This is particularly true of AM, who had the most discrimination scores at or below chance level.

Contrary to our predictions, then, contributing many misclassified sequences in Chapters 3 and 4

(thus, supposedly producing Exceptional Hiatus) does not necessarily translate into better

discrimination between Diphthong and Exceptional Hiatus (D_E and E_D pairs).


In this section we examine whether the identity of non-high vowel (V) in the vocalic sequences

under study has any effect on the proportion correct responses of the sequence and, if so, whether

the effect is different for Diphthongs and Hiatuses. Our prediction, based on results from

Chapters 3 and 4, is that sequences where V is [a] will be more difficult to distinguish than those

where V is either [e] or [o]. Figure 49 suggests, however, that the effect of V in the correct

discrimination of AX pairs was not exactly as we predicted.

[o][e][a]

1.0

0.8

0.6

0.4

0.2

0.0[o][e][a]

1.0

0.8

0.6

0.4

0.2

0.0[o][e][a]

1.0

0.5

0.0

-0.5

-1.0

p(c) A' ß?D


Figure 49. Bar chart of mean p(c), A' and β″D scores for V

B”D

206

The data in Table 60 confirms that, overall, discrimination scores were highest for sequences

with [o] (both p(c) and A′), followed closely by sequences with [a]. Discrimination scores were

lowest for V = [e]. In terms of bias, while the overall tendency was to respond Same for all level

of V, this bias was lowest for V = [o] and highest for V = [e]. The bias scores for V = [a] were

close to those for [o]. The differences between [e] and the other levels of V results in statistically

significant Friedman Test scores on the discrimination measures (both p(c) and A′). On the bias

measure, however, the differences between [e] and the other levels of V were not statistically

significant, even though β″D scores were higher for stimuli with [e] than for those with [a] or [o].

Table 60. Summary of p(c), A′ and β″D scores for V ([a], [e], [o])

V

Participant [a] [e] [o]

p(c)

AM 0.58 0.42 0.78

AN 0.83 0.56 0.86

DH 0.83 0.47 0.72

KR 0.92 0.61 0.94

LL 0.86 0.58 0.92

OVERALL

Mean = 0.80 Mean = 0.53 Mean = 0.84

Med. = 0.83 Med. = 0.56 Med. = 0.86

SD = 0.131 SD = 0.080 SD = 0.093


A′

AM 0.79 0.65 0.90

AN 0.92 0.79 0.93

DH 0.92 0.59 0.86

KR 0.96 0.81 0.97

LL 0.93 0.81 0.96

OVERALL

Mean = 0.90 Mean = 0.73 Mean = 0.92

Med. = 0.92 Med. = 0.79 Med. = 0.93

SD = 0.066 SD = 0.103 SD = 0.045


β″D

AM 0.88 0.96 0.84

AN 0.77 0.96 0.72

DH 0.77 0.71 0.74

KR 0.53 0.86 0.35

LL 0.72 0.95 0.53

OVERALL

Mean = 0.73 Mean = 0.89 Mean = 0.64

Med. = 0.77 Med. = 0.95 Med. = 0.72

SD = 0.128 SD = 0.108 SD = 0.195


207

Post-hoc comparisons (Wilcoxon Signed Rank Tests) between [a] and [e] (p = 0.059, for both

p(c) and A′) and between [e] and [o] (p = 0.059, for both p(c) and A′), however, fail to be

significant at the Bonferroni corrected α of 0.05/2 = 0.025. Still, these differences suggest a trend

that goes against our predictions for what the effects of the non-high vowel in the sequence (V)

would be. That is, rather than sequences with [a] being the most difficult to discriminate, it is

sequences with [e] which appear to cause more difficulty. In this case, all of the participants

followed the same trend, although AM lower values for p(c) and A′ for sequences with [a] than

the other four participants.

3.2.1 ISI and Stimulus Type Effects on V

When we examine the effects of ISI (500 vs. 1000) and Stimulus Type (Word vs. Sequence) in

combination with V (Figure 50), it appears that the V effect we observed above occurs for both

levels of ISI and both levels of Stimulus Type.

[o][e][a]

1.0

0.8

0.6

0.4

0.2

0.0[o][e][a]

1.0

0.8

0.6

0.4

0.2

0.0[o][e][a]

1.0

0.5

0.0

-0.5

-1.0

p(c) A' ß?D

ISI

500

1000

Word


[o][e][a]

1.0

0.8

0.6

0.4

0.2

0.0[o][e][a]

1.0

0.8

0.6

0.4

0.2

0.0[o][e][a]

1.0

0.5

0.0

-0.5

-1.0

p(c) A' ß?D

ISI

500

1000


Sequence

Figure 50. Bar chart of mean p(c), A' and β″D scores for V by ISI and Stimulus Type

Specifically, in all conditions stimuli with [e] have lower discrimination scores and higher

positive (Same) bias scores than stimuli with [a] or [o]. Bias scores for [a] and [o] stimuli, on the

other hand, are smaller and even show an overall negative (Different) bias (i.e. [a] Word stimuli

B”D B”D

208

at 500 ISI) or no bias (i.e. [o] Word stimuli at 1000 ISI) in some cases. However, for Stimulus

Type = Sequence, there appears to be an ISI effect where stimuli with [a] and [e] have higher

discriminations scores at 1000 ISI than at 500 ISI. In terms of bias, however, only stimuli with

[a] appear to benefit from the longer ISI in the Sequence condition. Sequences with [o] appear to

change little across conditions.

Accordingly, Friedman Test results (Table 61) show significant effects on all measures when all

the data are considered together.

Table 61. Summary of p(c), A′ and β″D scores for V, by Stimulus Type and ISI, across

participants

Word Sequence

ISI V Mean Median SD Mean Median SD

p(c)

500

[a] 0.87 1.00 0.243 0.69 0.67 0.167

[e] 0.53 0.56 0.097 0.40 0.44 0.098

[o] 0.87 0.89 0.092 0.87 0.89 0.143

1000

[a] 0.80 0.89 0.143 0.87 0.89 0.092

[e] 0.58 0.56 0.148 0.60 0.67 0.171

[o] 0.82 0.89 0.167 0.82 0.89 0.167


A′

500

[a] 0.84 0.93 0.189 0.76 0.77 0.153

[e] 0.62 0.65 0.118 0.43 0.50 0.152

[o] 0.88 0.90 0.040 0.87 0.90 0.069

1000

[a] 0.84 0.90 0.095 0.88 0.88 0.039

[e] 0.66 0.68 0.155 0.65 0.77 0.255

[o] 0.85 0.90 0.101 0.85 0.90 0.101

Friedman Test: S = 36.01 , df = 11, p = 0.000

β″D

500

[a] -0.04 -0.38 0.563 0.47 0.60 0.283

[e] 0.73 0.82 0.247 0.76 0.92 0.230

[o] 0.10 0.00 0.342 0.07 0.00 0.474

1000

[a] 0.25 0.00 0.369 0.03 0.00 0.393

[e] 0.69 0.67 0.191 0.72 0.67 0.211

[o] 0.00 0.00 0.500 0.17 0.00 0.461

Friedman Test: S = 27.50 , df = 11, p = 0.004

However, post-hoc Wilcoxon Signed Rank Tests (Table 62) fail to show any significant

between-vowel differences at the corrected α level of 0.004.

209

Table 62. Wilcoxon Signed Ranks Test results (Bonferroni corrections: α = 0.05/12 = 0.004)

for differences between levels of V by ISI and Stimulus Type

p-values

Stimulus Type ISI V p(c) A′ β″D

Sequence

500

[a] vs.[e] 0.100 0.100 0.201

[a] vs.[o] 0.201 0.201 0.201

[e] vs.[o] 0.059 0.059 0.106

1000

[a] vs.[e] 0.100 0.100 0.100

[a] vs.[o] 0.593 0.789 0.789

[e] vs.[o] 0.178 0.255 0.178

Word

500

[a] vs.[e] 0.100 0.100 0.100

[a] vs.[o] 0.855 0.855 0.855

[e] vs.[o] 0.059 0.059 0.059

[a] vs.[e] 0.059 0.059 0.059

1000 [a] vs.[o] 1.000 1.000 0.371

[e] vs.[o] 0.059 0.059 0.059

Similarly, there were no significant within-vowel differences, either for ISI or Stimulus Type

(Table 63), despite our earlier observations regarding the effect of ISI within the Sequence

condition when V = [e] or [a].

Table 63. Results of Wilcoxon Signed Ranks Test results (Bonferroni corrections: α =

0.05/6 = 0.008) for differences within levels of V by ISI and Stimulus Type

p-values

V ISI Stimulus Type p(c) A′ β″D

[a] 500 Word vs. Sequence 0.181 0.181 0.201

1000 Word vs. Sequence 0.593 0.855 0.584

[e] 500 Word vs. Sequence 0.100 0.100 1.000

1000 Word vs. Sequence 1.000 1.000 0.789

[o] 500 Word vs. Sequence 1.000 1.000 1.000

1000 Word vs. Sequence 1.000 0.893 0.686

Still, these tests suggest that most differences, although not statistically significant, occur

between levels of V and that at all levels of ISI and Stimulus Type, sequences with [a] and [o] are

discriminated with greater accuracy and sensitivity and with less bias than those with [e]. When

we look at the individual results (Table 64), we see that all of the participants follow this pattern.

210

Table 64. Summary of p(c), A′ and β″D scores for V by Stimulus Type and ISI, by

Participant

V

Word Sequence

ISI Participant [a] [e] [o] [a] [e] [o]

p(c)

500

AM 0.44 0.44 0.78 0.44 0.44 0.89

AN 0.89 0.67 0.78 0.89 0.44 0.78

DH 1.00 0.44 0.89 0.67 0.22 0.67

KR 1.00 0.56 0.89 0.78 0.44 1.00

LL 1.00 0.56 1.00 0.67 0.44 1.00

1000

AM 0.56 0.44 0.56 0.89 0.33 0.89

AN 0.78 0.56 1.00 0.78 0.56 0.89

DH 0.89 0.44 0.78 0.78 0.78 0.56

KR 0.89 0.78 0.89 1.00 0.67 1.00

LL 0.89 0.67 0.89 0.89 0.67 0.78

A′

500

AM 0.50 0.50 0.84 0.50 0.50 0.90

AN 0.90 0.77 0.84 0.90 0.50 0.84

DH 0.93 0.50 0.90 0.77 0.16 0.77

KR 0.93 0.65 0.90 0.84 0.50 0.93

LL 0.93 0.68 0.93 0.77 0.50 0.93

1000

AM 0.68 0.50 0.68 0.90 0.21 0.90

AN 0.84 0.68 0.93 0.84 0.68 0.90

DH 0.90 0.50 0.84 0.84 0.84 0.68

KR 0.90 0.84 0.90 0.93 0.77 0.93

LL 0.90 0.77 0.90 0.88 0.77 0.84

β″D

500

AM 0.92 0.92 0.43 0.60 0.60 0.00

AN 0.00 0.67 0.43 0.00 0.92 0.43

DH -0.38 0.92 0.00 0.67 0.43 0.67

KR -0.38 0.33 0.00 0.43 0.92 -0.38

LL -0.38 0.82 -0.38 0.67 0.92 -0.38

1000

AM 0.82 0.92 0.82 0.00 1.00 0.00

AN 0.43 0.82 -0.38 0.43 0.82 0.00

DH 0.00 0.60 -0.43 0.43 0.43 0.82

KR 0.00 0.43 0.00 -0.38 0.67 -0.38

LL 0.00 0.67 0.00 -0.33 0.67 0.43

3.2.2 Interactions between Pair Type and V

In this section, we test the interaction between Pair Type and V. Of particular interest is

determining whether the differences observed among levels of Pair type are attributable to V

differences. As before, we omit the same (A = X) pairs for all levels of V. When we consider all

211

possible combinations of Pair Type and V together, our results on all measures are statistically

significant (Table 65).

Table 65. Summary of p(c), A' and β″D scores for V by Pair Type, across participants

V

[a] [e] [o]

Pair Type Mean Median SD Mean Median SD Mean Median SD

p(c)

D_E 0.70 0.75 0.326 0.45 0.50 0.371 0.80 1.00 0.274

D_H 0.75 0.75 0.177 0.45 0.50 0.209 0.90 1.00 0.137

E_D 0.85 1.00 0.224 0.55 0.50 0.209 0.75 0.75 0.250

E_H 0.85 0.75 0.137 0.05 0.00 0.112 0.75 0.75 0.177

H_D 0.55 0.50 0.326 0.25 0.25 0.306 0.65 0.75 0.379

H_E 0.60 0.50 0.285 0.25 0.00 0.354 0.80 0.75 0.209


A′

D_E 0.84 0.89 0.116 0.68 0.79 0.273 0.87 0.93 0.077

D_H 0.88 0.89 0.052 0.76 0.79 0.098 0.91 0.93 0.022

E_D 0.89 0.93 0.061 0.80 0.79 0.095 0.87 0.89 0.071

E_H 0.91 0.89 0.022 0.31 0.22 0.197 0.88 0.89 0.052

H_D 0.79 0.79 0.126 0.53 0.66 0.298 0.81 0.89 0.142

H_E 0.81 0.79 0.105 0.47 0.22 0.341 0.89 0.89 0.057


β″D

D_E 0.41 0.40 0.419 0.68 0.75 0.396 0.30 0.00 0.411

D_H 0.39 0.40 0.266 0.74 0.75 0.208 0.16 0.00 0.219

E_D 0.23 0.00 0.338 0.64 0.75 0.230 0.38 0.40 0.375

E_H 0.24 0.40 0.219 0.98 1.00 0.040 0.39 0.40 0.266

H_D 0.59 0.75 0.392 0.84 0.91 0.252 0.44 0.40 0.456

H_E 0.56 0.75 0.365 0.83 1.00 0.264 0.31 0.40 0.317


Figures 51-53 suggests that many of these significant differences occur between levels of V, with

the largest differences between [a] and [e] or between [o] and [e].

212

H_EH_DE_HE_DD_HD_E

1.0

0.8

0.6

0.4

0.2


1.0

0.8

0.6

0.4

0.2


1.0

0.5

0.0

-0.5

-1.0

p(c) A' ß?D

V = [a]


Figure 51. Bar chart of mean p(c), A' and β″D scores for V by Pair Type, V = [a]

H_EH_DE_HE_DD_HD_E

1.0

0.8

0.6

0.4

0.2


1.0

0.8

0.6

0.4

0.2


1.0

0.5

0.0

-0.5

-1.0

p(c) A' ß?D

V = [e]


Figure 52. Bar chart of mean p(c), A' and β″D scores for V by Pair Type, V = [e]

B”D

B”D

213

H_EH_DE_HE_DD_HD_E

1.0

0.8

0.6

0.4

0.2


1.0

0.8

0.6

0.4

0.2


1.0

0.5

0.0

-0.5

-1.0

p(c) A' ß?D

V = [o]


Figure 53. Bar chart of mean p(c), A' and β″D scores for V by Pair Type, V = [o]

More specifically, for all Pair Types where A≠X, stimuli with [a] and [o] appear to be

discriminated more easily and with less bias than those with [e]. The results of the post-hoc

Wilcoxon Signed Ranks Tests of each level of Pair type in combination with each of V (Table

66), however, indicate that none of the differences between levels of V are statistically

significant at the corrected α levels.

B”D

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Table 66. Wilcoxon Signed Ranks Tests results (Bonferroni correction: α = 0.05/18 = 0.003)

for differences between levels of V by Pair Type

p-values

Pair Type V p(c) A′ β″D

D_E

[a] vs.[e] 0.345 0.225 0.345

[a] vs.[o] 0.715 0.584 0.715

[e] vs.[o] 0.100 0.100 0.100

D_H

[a] vs.[e] 0.181 0.181 0.181

[a] vs.[o] 0.181 0.181 0.181

[e] vs.[o] 0.059 0.059 0.059

E_D

[a] vs.[e] 0.100 0.100 0.100

[a] vs.[o] 0.371 0.371 0.371

[e] vs.[o] 0.100 0.100 0.100

E_H

[a] vs.[e] 0.059 0.059 0.059

[a] vs.[o] 0.465 0.361 0.584

[e] vs.[o] 0.059 0.059 0.059

H_D

[a] vs.[e] 0.059 0.059 0.059

[a] vs.[o] 0.715 0.715 0.715

[e] vs.[o] 0.181 0.181 0.181

H_E

[a] vs.[e] 0.138 0.106 0.281

[a] vs.[o] 0.273 0.201 0.361

[e] vs.[o] 0.059 0.059 0.059

Figures 51-53 also suggest that there are some differences in discrimination and bias according

to Pair Type within each level of V. For example, the ordering effect between Diphthong-Hiatus

(D_H) and Hiatus-Diphthong (H_D) pairs that we observed in §3.1.1 occurs within each level of

V. That is, with all vowels H_D pairs had lower discrimination and higher bias scores than D_H

pairs. On a similar note, the differences between Hiatus-Diphthong (H_D) and Exceptional

Hiatus-Diphthong (E_D) pairs observed in §3.1.1 (i.e. higher discrimination and lower bias

scores with the E_D pairs) also appears with all three levels of V. However, none of the post-hoc

Wilcoxon Signed Ranks Tests for the larger differences within each level of V were statistically

significant at the corrected α levels (Bonferroni corrections: α = 0.05/15 = 0.003) or even at the

original uncorrected α level of 0.05.

In summary, regardless of Pair type, when V is [e] (rather than [a] or [o]), discrimination

between different pairs will be more difficult, and often below chance level. This trend is evident

even when we consider the performance of each participant. As shown in Table 67, the lowest

discrimination and highest bias scores for most participants occur for V = [e]. This is the case not

only for those participants who generally had low discrimination and high bias scores (e.g. AM)

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but also for those who tended to have higher discrimination scores and lower bias scores (e.g.

KR). It is also only for this vowel that we see p(c) values of 0, A' values of 0.50 or below and

positive β″D values of 1.00.

Table 67. Summary of p(c), A' and β″D scores for V by Pair Type, by Participant

[a]


p(c)

AM 0.25 0.50 0.50 0.75 0.25 0.25

AN 0.50 0.75 1.00 1.00 0.75 0.50

DH 1.00 1.00 0.75 0.75 0.50 0.50

KR 0.75 0.75 1.00 1.00 1.00 0.75

LL 1.00 0.75 1.00 0.75 0.25 1.00

A′

AM 0.66 0.79 0.79 0.89 0.66 0.66

AN 0.79 0.89 0.93 0.93 0.89 0.79

DH 0.93 0.93 0.89 0.89 0.79 0.79

KR 0.89 0.89 0.93 0.93 0.93 0.89

LL 0.93 0.89 0.93 0.89 0.66 0.93

β″D

AM 0.91 0.75 0.75 0.40 0.91 0.91

AN 0.75 0.40 0.00 0.00 0.40 0.75

DH 0.00 0.00 0.40 0.40 0.75 0.75

KR 0.40 0.40 0.00 0.00 0.00 0.40

LL 0.00 0.40 0.00 0.40 0.91 0.00

[e]


p(c)

AM 0.00 0.50 0.50 0.00 0.00 0.00

AN 1.00 0.25 0.50 0.00 0.25 0.00

DH 0.25 0.25 0.25 0.25 0.25 0.75

KR 0.50 0.75 0.75 0.00 0.75 0.00

LL 0.50 0.50 0.75 0.00 0.00 0.50

A′

AM 0.22 0.79 0.79 0.22 0.22 0.22

AN 0.93 0.66 0.79 0.22 0.66 0.22

DH 0.66 0.66 0.66 0.66 0.66 0.89

KR 0.79 0.89 0.89 0.22 0.89 0.22

LL 0.79 0.79 0.89 0.22 0.22 0.79

β″D

AM 1.00 0.75 0.75 1.00 1.00 1.00

AN 0.00 0.91 0.75 1.00 0.91 1.00

DH 0.91 0.91 0.91 0.91 0.91 0.40

KR 0.75 0.40 0.40 1.00 0.40 1.00

LL 0.75 0.75 0.40 1.00 1.00 0.75

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Table 67 (cont’d)

[o]


p(c)

AM 0.50 0.75 0.50 0.75 1.00 0.50

AN 1.00 1.00 0.75 0.75 0.25 1.00

DH 0.50 1.00 0.50 0.50 0.25 1.00

KR 1.00 1.00 1.00 0.75 1.00 0.75

LL 1.00 0.75 1.00 1.00 0.75 0.75

A′

AM 0.79 0.89 0.79 0.89 0.93 0.79

AN 0.93 0.93 0.89 0.89 0.66 0.93

DH 0.79 0.93 0.79 0.79 0.66 0.93

KR 0.93 0.93 0.93 0.89 0.93 0.89

LL 0.93 0.89 0.93 0.93 0.89 0.89

β″D

AM 0.75 0.40 0.75 0.40 0.00 0.75

AN 0.00 0.00 0.40 0.40 0.91 0.00

DH 0.75 0.00 0.75 0.75 0.91 0.00

KR 0.00 0.00 0.00 0.40 0.00 0.40

LL 0.00 0.40 0.00 0.00 0.40 0.40


In this section the findings of the study are summarized and evaluated in terms of whether they

confirm the three hypotheses outlined at the beginning of the chapter.

4.1 Hypothesis 1: Diphthong vs. Hiatus

Hypothesis 1 stated that Diphthong and Hiatus belonged to different perceptual categories and

predicted that discrimination between them would be higher than discrimination between Hiatus

and Exceptional Hiatus which were supposed to not belong to separate perceptual categories. In

relation to the above hypothesis, we also predicted that discrimination between Diphthong and

Hiatus would benefit from a longer ISI, as this is thought to promote better between-category

distinctions (Pisoni, 1973; Werker & Tees, 1984; Werker & Logan, 1985; Gerrits & Schouten,

2004). Correspondingly, we predicted that discrimination between Exceptional Hiatus and Hiatus

would be best at a shorter ISI, which is thought to promote better within-category distinctions

(Pisoni, 1973; Werker & Logan, 1985). Also in relation to the primary hypothesis, we examined

whether presentation context (within a Word or as an isolated Sequence) affected discrimination

with the prediction that the Word context would yield better results.

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The results on measures of response accuracy, sensitivity and bias fail to confirm Hypothesis 1

and all of its related predictions as we found no statistically significant differences between any

of the A≠X Pair Types. Most importantly, we found no significant differences between

Diphthong and Hiatus pairs and Exceptional Hiatus and Hiatus pairs, despite the expectation that

the latter discrimination should be more difficult. There were also no significant differences

found according to ISI. Thus, the results for ISI could not be used to support the proposal that

diphthongs and hiatuses are separate perceptual categories while hiatuses and exceptional

hiatuses are not. Finally, hearing the stimuli in a Word context or in a Sequence context also had

no apparent effects on their perceptibility (in support of findings by Face & Alvord, 2004 and

Andruski & Nearey, 1992).

These statistically nil results may be to a large extent attributable to experiment design. First of

all, the sample size for the experiment was very small, resulting in decreased power and

contributing to the variability of the results. Second, both ISI and Stimulus Type were presented

in fixed order (i.e. 500 ISI before 1000 ISI; Word before Sequence). The decision to use a fixed

order of presentation makes it impossible to separate practice effects from any real differences

between levels of ISI and/or Stimulus Type from practice effects. Additional concerns about ISI

include: (i) its use as a within-subject factor and (ii) the small difference between the two levels

presented to the participants. With reference to the first concern, a better strategy might have

been to use a between-subjects design where one half the participants received the shorter ISI of

500 ms and the other half the longer ISI of 1000 ms (as suggested in Werker & Logan, 1985:39

for experiments where the effects of ISI on perceptual processing are tested). As regards the

second concern, the difference between 500 ISI and 1000 ISI may not be enough to affect

perception. For example, some authors suggest that the linguistic or labeling mode of perception

can be triggered at ISIs as short as 200 ms (Gerrits, 2001). Thus, the ISI of 500 ms used in the

present experiment may not have been short enough to make a significant difference. A better

choice may have been 250 ms vs. 1000 ms


Hypothesis 2 predicted that the quality of the non-high vowel (V) in the vocalic sequences used

in the stimuli would have perceptual consequences. The specific expectation was that sequences

here V = [a] would be the most difficult to discriminate, based on the behaviour of sequences

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with [a] in the acoustics and articulatory experiments (Chapter 3 and 4, respectively). On the one

hand, we do find support for this hypothesis. That is, the quality of the non-high V does

influence the responses. On the other hand, the V which was hardest to discriminate was not the

one predicted. That is, on all measures, participants did worse (i.e. they had lower accuracy and

sensitivity scores and higher bias scores) when the non-high vowel (V) in the stimuli was [e]

than when V was either [a] or [o]. This V effect was statistically significant and persisted across

ISI, Stimulus Type and Pair Type conditions. In addition, none of the participants deviated from

this pattern of poorer results for V = [e]. However, these results are tempered by the fact that

(possibly due to the effect of the small sample size) subsequent post-hoc tests for differences

between levels of V were not statistically significant.

4.3 Hypothesis 3: Production-Perception Link

The final hypothesis predicted that, just as we found individual variation in the production of

vocalic sequences in the experiments reported in Chapters 3 and 4, so too we would observe

individual variation in their perception. Specifically, we proposed that those participants who

consistently produced a higher number of misclassified Diphthong sequences (i.e. produced

Exceptional Hiatuses) in Chapters 3 and 4 would be better able to discriminate between

Diphthong and Exceptional Hiatus in an AX perception task than those who had fewer

misclassified Diphthong sequences. The results show that some participants do tend to have

higher accuracy and sensitivity scores and lower bias scores than others. Therefore, the first part

of the hypothesis appears to be accurate. However, contrary to our predictions, these were not the

same participants who produced the most misclassified sequences in the previous two chapters.

For example, AM was identified as being among those who produced the smallest Diphthong-

Hiatus differences and who contributed a large number of misclassified sequences (i.e.

Exceptional Hiatuses) in both Chapters 3 and 4. Thus, according to Hypothesis 3, she should

have been among the best performers on the perception task. In fact, she had the lowest

discrimination scores and highest bias scores across the most conditions with many of her

discrimination scores at chance or below chance level. Similarly, participants who had larger

Diphthong-Hiatus differences on the acoustic and articulatory measures (KR and LL, for

example) had higher discrimination scores and lower bias scores.

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4.4 Discussion

Overall, problems in the design of the present perception experiment make it difficult to

substantiate any strong claims about the results (regardless of whether they were statistically

significant and statistically nil). To recap, the small number of participants (as well as the small

number of trials per participant) resulted in low power for the experiment. Also, the fixed

ordering of presentation blocks made it difficult to tease apart any effects due to ISI (where

length was also an issue) or Stimulus Style from practice effects. Despite these problems,

however, there are some interesting patterns in the data which warrant some discussion.

First of all, for all levels of V we notice a possible stimulus ordering effect in stimuli pairs

consisting of Diphthong (D) and Hiatus (H). Specifically, participants generally have higher p(c)

and A′ scores with D_H pairs than with H_D pairs. While the difference is not statistically

significant, it raises the question of why it might exist at all. For example, the durational

differences between D_H and H_D are the same. Based on the differences in discrimination

between D_H and H_D we might conclude that hearing the shorter stimulus first exaggerates the

durational difference between D and H. Related to this observation is the possibility is that,

regardless of the durational properties of the stimulus itself, the first stimulus is always

remembered as having a shorter duration than it actually does (Francis & Ciocca, 2003, for

example, suggest that this is what occurs in perception of pitch in pairs of different tones in

Cantonese). Thus, if D is heard as shorter than it actually is, the difference between D and H is

exaggerated when D occurs first. However, if H is heard first and heard as shorter than it actually

is then the difference in duration between H and D is attenuated and participants perceive them

as more similar. Presentation order does not appear to affect H and E pairs which had equally

low mean p(c) values (0.55) regardless of which came first (Figure 48, Table 56). This pattern is

expected if we consider how close E and H are in terms of duration (§2, this chapter). Thus,

regardless of which is presented first, they become even closer in duration. This makes vowel

sequences forming a hiatus difficult to distinguish from those whose pattern resembles

exceptional hiatuses.

However, this explanation regarding the effect of presentation order on durational differences,

does not account for the following pattern also observed in the data. That is, participants

generally had higher p(c) and A′ scores with E_D (Exceptional Hiatus-Diphthong) pairs than

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with H_D (Hiatus-Diphthong) pairs. These differences are unexpected if we consider only how

Hiatus and Exceptional Hiatus differ from Diphthong in terms of duration and frequency

parameters. That is, given that Hiatus and Exceptional Hiatus are closer to each other on these

parameters than they are to Diphthong, we might expect them to behave similarly in pairs with

Diphthong. The fact that they don’t could be a reflection of the fact that Exceptional Hiatus is

not common in this variety of Spanish (Chapter 1) and its relative ‘strangeness’ may make it

stand out to the listener. This might also explain why there was no obvious ordering effect

observed between E_D and D_E pairs to match the one found between D_H and H_D pairs.

Second, we observed that some of the Pair Type effects we discussed above were influenced by

the identity of V as well since they tended to occur mainly for V = [e]. For example, the worst

results for Hiatus and Exceptional Hiatus pairs (E_H and H_E, especially the former) were found

for V = [e]. Thus, it may be the case that perception of exceptional hiatuses also depends on

vowel context. That is, when V = [e], exceptional hiatuses essentially fall into the category of

hiatuses and cannot be discriminated from them. On the other hand, when V is [a] or [o],

exceptional hiatuses are easier to discriminate, and thus to perceive as different, from hiatuses.

This pattern can be explained if we consider that in those Spanish varieties where exceptional

hiatuses are common, most of them occur with [a] or, less frequently, with [o] as the non-high

vowel (e.g. Hualde, 2005). Exceptional hiatuses with [e], on the other hand, are less likely to

occur (as supported by the Discriminant Analysis results in Chapters 3 and 4). Thus, although

these sequences are present in the stimuli in equal numbers as corresponding sequences with [a]

and [o], they may occur less frequently in natural language situations. The result of this

discrepancy between the experimental situation (in the context of the AX task used here) and a

natural language situation might be that the participants perceive exceptional hiatuses with [e] as

identical to hiatuses with [e].

Finally, we observe an asymmetry between the perception of vocalic sequences in Mexican

Spanish and the production of the same sequences. That is, neither the sequence-specific nor the

participant-specific patterns observed in this experiment seem to match the results from the

production chapters. First, the V effects found here suggest that the small acoustic and

articulatory differences that resulted in Discriminant Analysis misclassification in Chapters 3 and

4 may not be the same differences that are perceptually relevant to the participants as listeners.

Second, the participant-specific patterns of responses we observe here differ from the patterns we

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observed from the same participants on the production tasks. That is, distinctness in production

(i.e. producing Exceptional Hiatuses) does not match perceptual acuity (i.e. better ability to

discriminate between Diphthong and Exceptional Hiatus) on the AX task. The present results are

in contradiction to studies which report a link between perceptual acuity and contrast in

production (Beddor et al., 2002; Beddor, 2012; Newman, 2003; Perkell et al., 2004a, 2004b,

2006). However, it is important to note that those studies generally focused on strong phonemic

contrasts while the phonemic status of the contrasts examined here is questionable. The results

reported in this chapter are also at odds with previous research on vocalic sequences for

Peninsular Spanish (e.g. Hualde & Prieto, 2002; Face & Alvord, 2004) and other Romance

varieties (Chitoran, 2002). Those studies have found that participants’ perception of these

sequences (tested through syllabification and/or labelling asks) is generally consistent with their

production of the same sequences. One possible source for the discrepancy between this study

and those cited above for Peninsular Spanish is experiment methodology. That is, the difference

in results may reflect the type of perception task used (discrimination used here vs. identification

and/or syllabification in the Peninsular Spanish studies). However, issues in the design of the

perception experiment carried out for the present dissertation make it impossible to substantiate

any strong claims about the results.

5 Conclusions

A principal objective of this dissertation was to investigate the link between variation in the

production of vocalic sequences in Mexican Spanish and variation in the perception of the same

sequences. The present experiment did not produce the expected results with regards to this

objective, in large part due to the experiment design. However, despite the methodological

shortcomings and the highly variable results, the experiment does reveal some interesting

patterns which merit further investigation, especially where V effects are concerned. In the

following chapter, we explore the possibility that the production-perception asymmetry reported

here may in part be a result of the acoustic and articulatory parameters chosen to differentiate

between categories of vocalic sequences in the Discriminant Analysis as well as to dialect-

specific properties of [e].

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Chapter 6 Conclusions

1 Introduction

This dissertation has investigated the variation present in the production and perception of

vocalic sequences in Mexican Spanish, with an emphasis on the relationship between this

variation and the occurrence of exceptional hiatuses. This chapter revisits the research goals

which motivated the dissertation, reviews and interprets the findings of the three experimental

chapters in light of those goals, discusses the contributions of those experimental findings and

offers suggestions for continued research in the area of Spanish vocalic sequences.

2 Summary of Findings

The central research goals of this dissertation (restated from Chapter 1) were to demonstrate that:

(i) The phonetic variation responsible for the occurrence of exceptional hiatuses is present in

all Spanish varieties, including those varieties described as having a high

diphthongization tendency.





To achieve the above research goals, three experiments were conducted. The first experiment

(Chapter 3) focused on the acoustic characterization of vocalic sequences in Mexican Spanish,

the second experiment (Chapter 4) examined the articulatory characteristics of these sequences,

and the third experiment (Chapter 5) focused on their perception. The specific hypotheses tested

with each experiment were evaluated at the end of their respective chapters. Here, we offer an

overview of the most important findings from the three experiments and evaluate whether these

findings are in agreement with the three research goals stated above.

2.1 Phonetic Variation and Exceptional Hiatuses

In support of the first research goal, we found sequence-specific and speaker-specific variation in

the production of diphthongs and hiatuses in Mexican Spanish, both at the acoustic level

(Chapter 3) and at the articulatory level (Chapter 4).

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2.1.1 Sequence-specific Variation

The sequence-specific variation was related to the behaviour of the non-high vowel (V) in the

sequences. That is, sequences with [a] tended to behave differently from sequences with [e] or

[o], both on the acoustic and on the articulatory measures. Specifically, sequences with [a]

showed more extreme values than sequences with [e] or [o]. For example, diphthongs with [a]

were longer and had shorter transitions than their counterparts with [e] and [o]. Similarly,

hiatuses with [a] had larger Tongue Body (TB)-Tongue Tip (TT) offset values than hiatuses with

either [e] or [o]. The degree of differences between Diphthong and Hiatus categories also varied

according to V and tended to be smallest for sequences with [a]. We suggested that this

sequence-specific variability in diphthong and hiatus production likely reflects the articulatory

properties of the non-high V ([a,e,o]) in these sequences. That is, the longer tongue/jaw

trajectories required for sequences with the low vowel [a] result in more extreme values on the

acoustic and articulatory measures as well as smaller Diphthong-Hiatus differences for

sequences with [a].

It is important to point out, however, that the sequence-specific variation related to the behaviour

of the non-high V in the sequences was not completely regular. For example, the Diphthong-

Hiatus differences showed the above V effects on all acoustic measures. In the articulation

results, the difference between Diphthong and Hiatus also appeared to be influenced by the

identity of V, but not as dependably and only on one measure (TB-TT offset). These differences

between the acoustics and articulation results are discussed in more detail in §2.2 below.

Despite these inconsistencies, however, the sequence-specific variation does produce an

important result. That is, as a consequence of their articulatory properties (as described above),

diphthongs with [a] were more likely than diphthongs with [e] or [o] to be misclassified as hiatus

by the Discriminant Analysis procedure. This result was found in both the acoustics and

articulation experiments and is consistent with the observation that most cases of exceptional

hiatuses occur when V = [a] (e.g. Hualde, 2005; Chitoran & Hualde, 2007). Overall, then, the

above results support the hypothesis that phonetic variation is at the root of the occurrence of

exceptional hiatuses (i.e. the misclassified diphthongs in the experiments). The results are also in

accordance with the hypothesis that this variation is also found in diphthongizing varieties of

Spanish, like Mexican Spanish. These varieties, too, produce exceptional hiatuses.

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Another important observation arising from the Discriminant Analysis is that any diphthong

could be realized as an exceptional hiatus, regardless of historical origin. For example, among

words with diphthongs where V = [e], prieto, pliegue and bienes had several misclassified cases.

This is unexpected since the diphthongs in all these words are derived from breaking of the Latin

short mid vowel Ĕ and the general consensus in Spanish phonology (e.g. Chitoran & Hualde,

2007, p. 46; Cabré & Prieto, 2006, p. 208) is that all such sequences are obligatorily realized as

diphthongs. In fact, in the experiments reported in this dissertation these diphthongs behaved no

differently from the diphthong in the word cliente which is derived from a Latin heterosyllabic

sequence and, thus, expected to be realized with an exceptional hiatus.

2.1.2 Speaker-specific Variation

In terms of speaker-specific variation, we found that those speakers who maintained larger

Diphthong-Hiatus differences tended to contribute fewer misclassified Diphthong sequences. In

other words, they produced fewer sequences that could be considered exceptional hiatuses. In

addition, those who had larger Diphthong-Hiatus differences on the acoustic measures also

tended to have large differences on the articulatory measures. However, the evidence from

individual variation, like that from the sequence-specific variation, was not completely

consistent. For example, the relationship between a larger Diphthong-Hiatus difference and

fewer misclassified sequences did not always hold. To illustrate, Speaker DH, who maintained

relatively large Diphthong-Hiatus differences on the acoustic and articulatory parameters

contributed several misclassified sequences. This suggests that while maintaining a small

Diphthong-Hiatus contrast on these parameters may generally be associated with more

misclassified sequences (and, by extension, more exceptional hiatus production), it is not a

necessary precursor. It may be that a small Diphthong-Hiatus contrast is not necessary at all or

that some participants are making use of phonetic strategies not measured and/or not captured in

the Discriminant Analysis to maintain this contrast. In addition, we also found that while some

speakers consistently maintained a similar acoustic and articulatory distance between Diphthong

and Hiatus across vowel contexts (i.e. contributed similar numbers of misclassified sequences for

the three levels of V), others behaved differently according to the identity of V. As an example,

Speaker AM had many misclassified cases of diphthongs for both V = [a] and V = [e]. On the

other hand, speakers MM and MV, who also contributed many misclassified sequences with

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V = [a], had very few cases with V = [e]. The perceptual consequences, and/or lack thereof, of

these inconsistencies are examined in §2.3.

2.2 Articulation and Exceptional Hiatuses

Our second research goal too received some support, with the evidence from the articulation

experiment both confirming and contradicting results from the acoustics experiment. For

example, as in the acoustics experiment, we found that sequences with [a] were more likely to be

misclassified than sequences with [e] or [o]. However, the results from the articulation

experiment also differ from the acoustics result in an important way. The Discriminant Analysis

results for the articulation data found that more hiatuses were misclassified as diphthongs than

vice versa. This contrasts with our findings from the acoustics experiment where diphthongs

were more likely to be misclassified than hiatuses as well as be more susceptible to the influence

of the non-high vowel in the sequence. In short, hiatuses appear to be more variable at the

articulatory level while diphthongs appear more variable at the acoustic level (Chapter 4, §4.4).

Since the acoustics are directly based on articulation (e.g. Browman & Goldstein, 1992), the

difference in results may be explained by (i) the different techniques used in the two

experiments, and (ii) the articulatory parameters measured. First, the articulation data looked at

the actions of specific articulators (TB and TT) without the contribution of the JAW while the

acoustic effects reflect the actions of several articulators (including the JAW) acting together

(Chapter 4, §4.4). In addition, the acoustic measurements are a reflection of multiple articulatory

parameters, some of which may fall in regions of acoustic instability, where small articulation

changes cause large acoustic effects (e.g. Stevens, 1989). We did not measure all of these

possible parameters in the articulation experiment, focusing only on TB-TT offset and the

magnitude of TB and TT gestures and these only for the vertical (up-down) dimension.

However, it may also be the case that some of the acoustic effects may not necessarily be

relevant to the Diphthong-Hiatus distinction. In fact, the mismatch between the acoustic and

articulation results may be viewed as reconciling the apparent contradictory propensities of

diphthongs. That is, while diphthongs appear to be more acoustically variable than hiatuses

(MacLeod, 2007), they are, in fact, articulatorily more stable than hiatuses (Chitoran & Hualde,

2007). The articulatory stability is primary and is consistent with the tendency for hiatuses to

diphthongize across Spanish dialects (e.g. Hualde et al., 2008; Garrido, 2007, 2008). However,

since most research on Spanish vocalic sequences looks at acoustic evidence, the acoustic

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variability is what is most apparent and what is reported. This variability may, in turn, affect the

number of sequences identified in the literature as exceptional hiatuses. That is, it may lead to an

overestimation of the occurrence of exceptional hiatuses, as suggested in Chapter 2 (§2.3).

Additionally, in support of proposals by Chitoran & Hualde (2007) and Nevins & Chitoran

(2008), the results from the articulation experiment provides preliminary evidence that the

Diphthong-Hiatus contrast in Mexican Spanish can be achieved through differences in the

temporal coordination of TB and TT gestures and in the magnitude of the TT gesture. In fact, we

highlighted the importance of the actions of the TT which we suggested was responsible for both

the Diphthong-Hiatus contrast as well as the diphthongization process (Chapter 4, §4.4). This

evidence, of course, is tempered by the observation that the data was highly variable. To reduce

some of this variability, especially the effects of following consonants, measurements were

modified. However, these adjustments raise the question of the appropriateness of the modified

measurements. Thus, more research is warranted to determine how well the chosen

measurements capture the Diphthong-Hiatus contrast.

Overall, however, the findings from the articulation experiment reported in this dissertation

highlight the value of experimental articulatory research to test specific questions related to

Spanish phonology and phonetics. In the present case, we have shown that the behaviour of

vocalic sequences in Spanish can be understood more fully when their articulatory and acoustic

properties are studied together. An investigation of the perception of these sequences completes

the picture and is discussed next.

2.3 Production-Perception Link

The experimental evidence in the present study does not support the third research goal of

establishing a production-perception link for vocalic sequences in Mexican Spanish. This goal

was based on two assumptions. The first assumption was that the participants’ production of

misclassified sequences was related to their perception of these sequences (e.g. Hualde & Prieto,

2002; Face & Alvord, 2004). In other words, the expectation was that a speaker who produced

many misclassified Diphthong tokens (i.e. more exceptional hiatuses) would be better able to

discriminate between Diphthong and Exceptional Hiatus in a perception task. The second

assumption was that perceptually distinctive contrasts could be identified through discriminant

analysis (Port & Crawford, 1989; Faber & DiPaolo, 1995; Morrison, 2006). Thus, the

227

expectation here was that those sequences identified as ambiguous and misclassified by the

discriminant analysis procedure, would be similarly subject to misclassification by listeners in a

perception experiment. In particular, we expected sequences with [a] to have lower

discrimination scores than sequences with [e] or [o] since the former were more likely to be

misclassified in the discriminant analysis.

In fact, with regards to the first assumption, participants performed similarly for all Pair types in

the AX perception task, regardless of whether they produced few or many misclassified

sequences in the production studies. That is, participants who produced many misclassified

diphthongs were not statistically more likely to accurately perceive a difference between

Diphthong and Exceptional Hiatus than participants who produced fewer misclassified

diphthongs. In fact, participant AM (who maintained small Diphthong-Hiatus differences and

contributed a large number of misclassified diphthongs in both production experiments) achieved

lower discrimination scores than participants who had larger Diphthong-Hiatus differences on

the acoustic and articulatory measures (KR and LL). In addition, regarding the second

assumption, the vowel with which participants had the most difficulty was [e], not [a] as

predicted from the acoustic and articulation studies.

These results would appear to be in contradiction to studies which find links between perceptual

acuity and contrast in production (Beddor et al., 2002; Beddor, 2012; Newman, 2003; Perkell et

al., 2004a, 2004b, 2006)70

. They are also in contradiction of previous studies on Spanish vocalic

sequences which have found that participants’ perception of these sequences (tested through

syllabification and/or labelling asks) is generally consistent with their production of the same

sequences (e.g. for Peninsular Spanish: Hualde & Prieto, 2002; Face & Alvord, 2004). However,

issues in the design of the perception experiment carried out for the present dissertation make it

impossible to substantiate any strong claims about the results. First and foremost, the small

number of participants (N = 5) as well as the small number of trials per participant (108) make

the results more susceptible to variation, greatly reducing the statistical power of the experiment.

In addition, both Stimulus Type (Word vs. Sentence) and ISI (500 vs. 1000) were presented as

within-subject factors. More importantly, the blocks in which these factors were combined were

70 Although, as noted in Chapter 5 (§4.4), this discrepancy may simply reflect differences in the type of contrast being examined.

228

presented in fixed order (Chapter 5, §2.2) to all the participants (although the order of trials

within each block was randomized for each participant). In combination, these methodological

limitations make it difficult to confirm any of the observed effects.

As a final observation, it is possible that the production-perception asymmetry found may be a

result of the parameters chosen to differentiate between categories of vocalic sequences in the

Discriminant Analysis. It may be that in order to establish a production-perception link for

Mexican Spanish different acoustic and articulatory parameters need to be included since they

may be more perceptually relevant to Mexican Spanish speakers. Two possible acoustic

parameters are suggested in §4 below.

The production-perception asymmetry observed with V effects points to the importance of such

dialect-specific considerations. Specifically, there are indications that this asymmetry may be

due to dialect-specific phonetic properties of [e]. Data collected from speakers of other varieties

of Spanish during the perception experiment (Chapter 5, footnote 68) suggests that these other

varieties also experience more difficulty with sequences with [e], but only when the Speaker is

Mexican (Figure 54, middle panel).

p(c

)

PENMEXARG

1.0

0.8

0.6

0.4

0.2

0.0PENMEXARG PENMEXARG

Speaker = ARG Speaker = MEX Speaker = PEN

V

a

e

o

Listener

Figure 54. Bar chart of mean p(c) scores for V, by Speaker Dialect and Listener Dialect

229

Although the above data is very preliminary (only proportion correct values were calculated) and

come from a single Peninsular Spanish speaker and only two Argentine Spanish speakers, the

pattern with Mexican Spanish [e] remains the same across Listener dialect. That is, when the

Speaker is Mexican, all listeners (Mexican, Argentine and Peninsular) perform worse with

sequences with [e] than for sequences with [a] and [o]. This suggests that in Mexican Spanish

there is something about vocalic sequences with this vowel that makes them difficult to

distinguish from each other. As we saw in Chapter 3, for example, the absolute formant change

in the F1-F2 contours of sequences with [e] (both diphthongs and hiatuses) is less than for

sequences with [a] and [o]. It may also be the case that Mexican [e] is more [i]-like than in other

varieties, partially explaining why this variety exhibits such advanced diphthongization of mid-

vowel hiatuses (resulting in words like teatro, ‘theatre’ being pronounced as [teá.tɾo] or even

[tjá.tɾo] rather than with the expected hiatus, as in [te.á.tɾo]: see Chapter 1, §4.1; Chapter 2, §2.

1). Some researchers have observed an overlap between [e] and [i] in syllable-initial position in

sequences with a following [a] ([ea] vs. [ia] sequences) in this variety of Spanish, but only in

duration (Garrido, 2008). Still, this similarity in duration may be perceived by listeners as a

similarity in vowel height and/or fronting (Gussenhoven, 2007) and add to the difficulty in

processing and interpreting sequences with [e] in combination with [i] or [j]. Further

investigation of perception (and production) data from different dialects of Spanish would be

needed to test the proposals outlined in this section.

3 Contributions

Despite the methodological concerns and the variability found in the results, this dissertation

contributes to an understanding of vocalic sequences in Spanish in the following ways.

3.1 Empirical Contributions

First, the dissertation adds to existing acoustic data on vocalic sequences in Spanish by

investigating Mexican Spanish, a dialect more often cited in studies of hiatus resolution (e.g.

Alba, 2006) and diphthongization (e.g. Garrido, 2008) than in studies concerning exceptional

hiatuses. More importantly, the dissertation complements existing acoustic characterizations of

these sequences with articulatory data. In combination, the results from the acoustic and

articulation experiments highlight the role of phonetic variation in the production of diphthongs

and hiatuses as the necessary precursor for exceptional hiatuses and provide support for the

230

proposal that this variation is present in all Spanish varieties, including those (like Mexican

Spanish, the variety which was the focus of the dissertation) with an advanced diphthongizing

tendency.

3.2 Theoretical Contributions

The above findings have important theoretical implications. First, the phonetic variation found in

the production of these sequences suggests that exceptional hiatuses can be thought of as

phonetic variants of diphthongs. That is, exceptional hiatuses simply reflect instances of the

low-level phonetic coarticulation that occurs as a consequence of the movement from a glide (a

high vocoid) to a non-high vowel in the articulatory space (Van Heuven & Hoos, 1991). As

such, exceptional hiatuses may occur in any dialect or variety of Spanish, including those with

advanced diphthongization tendencies. In addition, since the movement from glide to vowel is

greatest when the non-high vowel is [a], this would account for the tendency for exceptional

hiatuses to occur more often for words with [ja] sequences. Furthermore, the results suggest that

any diphthong (regardless of etymological origin) can be produced with exceptional hiatus in the

contexts tested here, including diphthongs (i.e. [je]) derived from the breaking of Latin short mid

vowels. This finding is counter to the assertion that these historic diphthongs are realized,

without exception, as diphthongs (Chitoran & Hualde, 2007; Cabré & Prieto, 2006). More

importantly, taken together, the findings described above call into question the need for a special

category of exceptional hiatuses and challenge the long-standing notion in Spanish phonology

that words which may surface with exceptional hiatus need to be lexically marked (e.g. Harris &

Kaisse, 1999; Hualde, 2005). Finally, the observation that diphthongs display more articulatory

stability than hiatuses contributes to an explanation of the change from [iV]> [jV] in the history

of the Spanish language.

3.3 Methodological Contributions

Through the combined use of various experimental techniques (including normalization

procedures, EMA, discriminant analysis, signal detection measures, and AX perception tasks)

the research reported here also make methodological contributions to existing studies of Spanish

vocalic sequences and opens the door to the application of these methodologies to future

examinations of production and perception of vocalic sequences in Spanish.

231

4 Future Directions

Any future experiments would need to correct the methodological shortcomings identified with

the experiments conducted for this dissertation, especially in the articulation and perception

experiments. The possible dialect-specific considerations identified in §2.3 suggest that future

experiments need to also consider testing additional acoustic and articulatory parameters for

inclusion in the Discriminant Analysis. Additional acoustic parameters may include intensity and

pitch. For example, Lehiste (1967), in her study of Estonian, found that intensity peaks reliably

differentiated between V + V sequences (which showed one peak for each V) and diphthongs

(with a single intensity peak) in that language, regardless of vowel quality. Similarly, Mauder &

van Heuven (1996) reported that peak f0 position and f0 movement patterns for a Chilean

Spanish speaker differed for falling diphthongs and hiatuses (e.g. [áj] vs. [a.í]). Finally, the

results from the perception experiment underscore the need to test a larger pool of participants

and to compare the results of participants from different dialects of Spanish. In short, the

findings of this dissertation point to the necessity of continued research on the articulatory

properties of vocalic sequences and on the production-perception link for these sequences for

different varieties of Spanish.

232

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Appendices

Appendix 1: Experiment Stimuli (Chapters 3 and 4)

Category Word Gloss V

Diphthong

(N= 7)

viaje trip a

viejo trip a

pieza piece/room e

prieto dark e

pliegue fold e

bienes goods e

viola viola o

Hiatus

(N=4)

días days a

crías baby animals a

ríen they laugh e

ríos rivers o

Possible Exceptional Hiatus

(N=9)

diablo devil a

criada maid a

diario newspaper a

piano piano a

piada chirping a

cliente client e

bienio 2-year period e

piojo louse o

criollo Creole o

Distractor

(N=15)

pesa weight e

presa dam/prey e

plena full e

pisa s/he steps on i

prisa hurry/rush i

plisa s/he pleats i

pasa s/he goes by a

prado field a

plaza main square a

posa s/he poses o

prosa prose o

plomo lead o

puso s/he put u

pruna prune u

pluma feather u

Practice Word

(N=5)

lavo I wash a

fuego fire e

lago lake a

lado side e

juego game a

247

Appendix 2: Table of Individual Means and Standard Deviations (Chapter 3)

Table A2.1. Means and SDs of Raw Sequence Durations, by Rate

Speaker

Rate 1 Rate 2

Diphthong Hiatus Difference


Mean SD Mean SD Mean SD Mean SD

AA 192.23 43.61 231.64 28.43 39.41 184.19 42.13 247.59 20.87 63.40

AM 185.88 41.45 227.59 30.48 41.71 148.44 44.07 194.61 20.16 46.17

AN 139.59 32.42 196.72 19.27 57.13 130.01 35.34 183.85 10.18 53.84

CG 113.06 16.41 162.91 14.54 49.85 100.23 14.09 152.54 11.19 52.31

DH 100.80 18.64 147.92 26.65 47.12 79.52 14.75 128.33 22.50 48.81

KR 114.50 29.99 166.09 11.00 51.59 111.80 25.21 166.16 10.70 54.36

LG 119.03 23.43 158.09 14.28 39.06 110.70 20.66 145.19 12.03 34.49

LL 131.97 30.26 181.01 22.57 49.04 118.94 23.65 141.88 17.14 22.94

MM 123.99 36.26 140.88 18.30 16.89 103.00 31.82 142.88 16.09 39.88

MV 156.80 23.84 164.43 16.72 7.63 126.04 28.65 154.37 10.22 28.33

Total 137.86 42.76 177.73 36.26 39.87 121.34 40.32 165.74 36.71 44.40

Table A2.2. Means and SDs of Normalized Sequence Durations, by Rate

Speaker

Rate 1 Rate 2




AA 0.28 0.92 1.11 0.60 0.83 0.11 0.89 1.45 0.44 1.34

AM 0.58 0.89 1.48 0.66 0.90 -0.23 0.95 0.77 0.43 0.99

AN 0.18 0.87 1.72 0.52 1.53 -0.08 0.95 1.37 0.27 1.45

CG 0.21 0.62 2.10 0.55 1.89 -0.27 0.53 1.71 0.42 1.98

DH 0.26 0.71 2.05 1.01 1.78 -0.54 0.56 1.31 0.85 1.85

KR 0.06 0.95 1.69 0.35 1.63 -0.03 0.80 1.69 0.34 1.72

LG 0.22 0.89 1.70 0.54 1.48 -0.10 0.78 1.21 0.46 1.31

LL 0.38 0.91 1.85 0.68 1.47 -0.01 0.71 0.68 0.52 0.69

MM 0.50 1.06 0.99 0.53 0.49 -0.11 0.93 1.05 0.47 1.16

MV 0.70 0.82 0.96 0.57 0.26 -0.35 0.98 0.62 0.35 0.97

Total 0.34 0.88 1.57 0.72 1.23 -0.16 0.83 1.19 0.60 1.34

Table A2.3. Means and SDs of Normalized Sequence Durations for V= [a], by Rate

Speaker

Rate 1 Rate 2




AA 0.58 0.54 1.38 0.65 0.81 0.34 0.55 1.18 0.31 0.83

AM 0.99 0.58 1.91 0.59 0.93 0.19 0.81 0.97 0.38 0.79

AN 0.55 0.54 2.01 0.58 1.46 0.00 0.42 1.37 0.31 1.37

CG 0.52 0.49 1.98 0.72 1.46 0.05 0.59 1.49 0.46 1.44

DH 0.56 0.78 2.86 0.57 2.30 -0.21 0.59 1.62 0.85 1.83

KR 0.39 0.38 1.84 0.36 1.44 0.25 0.51 1.85 0.31 1.61

LG 0.77 0.89 2.00 0.59 1.23 0.36 0.75 1.51 0.45 1.15

LL 0.94 1.06 2.18 0.82 1.24 0.16 0.76 0.77 0.73 0.61

MM 1.22 1.17 1.34 0.56 0.12 0.45 0.93 1.36 0.41 0.9

MV 1.17 0.86 1.01 0.46 -0.16 0.08 0.70 0.76 0.33 0.68

Total 0.77 0.8 1.85 0.74 1.08 0.17 0.69 1.29 0.57 1.12

248

Table A2.4. Means and SD of normalized sequence durations for V= [e], by Rate

Speaker

Rate 1 Rate 2




AA 0.03 1.24 0.79 0.40 0.76 -0.11 1.19 1.47 0.32 1.58

AM 0.34 1.11 1.04 0.47 0.71 -0.43 1.11 0.42 0.40 0.85

AN 0.06 1.07 1.43 0.09 1.37 -0.12 1.32 1.36 0.28 1.47

CG -0.12 0.66 2.33 0.44 2.45 -0.58 0.35 1.84 0.01 2.42

DH 0.15 0.45 0.76 0.28 0.61 -0.71 0.30 0.30 0.29 1.00

KR 0.02 1.30 1.68 0.34 1.66 -0.09 1.05 1.52 0.44 1.61

LG -0.17 0.61 1.23 0.33 1.40 -0.43 0.63 0.88 0.29 1.31

LL 0.09 0.47 1.34 0.22 1.25 -0.02 0.65 0.55 0.10 0.57

MM 0.05 0.83 0.70 0.20 0.65 -0.37 0.76 0.59 0.38 0.96

MV 0.33 0.58 1.56 0.06 1.23 -0.66 1.16 0.40 0.22 1.06

Total 0.08 0.89 1.29 0.55 1.21 -0.34 0.93 0.93 0.60 1.28

Table A2.5. Means and SD of normalized sequence durations for V= [o], by Rate

Speaker

Rate 1 Rate 2




AA 0.26 0.44 0.88 0.58 0.62 0.12 0.54 1.97 0.31 1.84

AM 0.33 0.51 1.04 0.36 0.71 -0.57 0.4 0.7 0.45 1.28

AN -0.26 0.65 1.42 0.35 1.68 -0.12 0.73 1.39 0.32 1.51

CG 0.28 0.47 2.11 0.25 1.83 -0.33 0.32 2.02 0.39 2.35

DH -0.05 0.89 1.71 0.25 1.76 -0.82 0.68 1.68 0.26 2.50

KR -0.52 0.33 1.41 0.23 1.93 -0.41 0.31 1.55 0.21 1.96

LG 0.01 0.94 1.57 0.16 1.56 -0.22 0.8 0.95 0.14 1.17

LL -0.17 0.68 1.71 0.24 1.89 -0.35 0.72 0.62 0.22 0.97

MM 0.13 0.34 0.59 0.06 0.47 -0.69 0.71 0.91 0.15 1.60

MV 0.52 0.74 0.28 0.18 -0.24 -0.59 0.83 0.57 0.47 1.16

Total 0.05 0.67 1.27 0.60 1.22 -0.39 0.66 1.24 0.59 1.63

Table A2.6. Means and SD of %Transition, by Rate

Speaker

Rate 1 Rate 2




AA 44.05 11.94 31.76 3.71 12.29 42.33 9.01 29.18 7.24 13.15

AM 40.95 10.96 29.22 6.53 11.73 40.19 9.04 29.80 6.60 10.39

AN 46.44 12.53 27.48 6.19 18.96 44.83 13.85 35.13 5.62 9.70

CG 42.34 10.96 39.12 5.49 3.22 43.37 12.82 39.26 7.49 4.11

DH 52.02 10.08 41.69 8.31 10.33 56.77 16.23 41.56 6.13 15.21

KR 57.50 16.75 35.75 6.32 21.75 47.50 14.55 35.03 4.93 12.47

LG 45.35 13.88 33.84 9.27 11.51 48.38 12.53 31.92 6.00 16.46

LL 50.59 10.90 35.32 6.18 15.27 47.15 11.19 36.96 8.08 10.19

MM 50.00 11.66 37.64 12.94 12.36 52.91 14.71 39.34 7.17 13.57

MV 43.82 9.80 30.25 4.89 13.57 51.34 13.67 38.86 5.74 12.48

Total 47.34 12.97 34.21 8.35 13.13 47.49 13.73 35.71 7.51 11.78

249

Table A2.7. Means and SDs of %Transition for V= [a], by Rate

Speaker

Rate 1 Rate 2




AA 38.45 9.07 33.03 4.45 5.42 42.83 7.62 32.33 7.05 10.50

AM 36.06 6.22 28.56 4.01 7.50 37.66 6.19 30.58 3.52 7.08

AN 40.18 11.65 26.89 6.36 13.29 39.85 12.59 35.43 7.95 4.42

CG 42.67 7.65 35.88 3.30 6.79 39.70 7.56 39.75 4.85 -0.05

DH 52.59 9.95 39.45 6.98 13.14 53.89 13.63 38.99 5.13 14.90

KR 49.81 9.90 31.29 5.19 18.52 50.26 10.02 33.71 5.82 16.55

LG 42.93 10.93 40.02 9.09 2.91 44.28 8.09 33.33 7.36 10.95

LL 49.05 12.21 33.82 4.67 15.23 47.52 12.02 38.50 8.30 9.02

MM 45.75 8.51 36.46 8.63 9.29 49.68 9.98 41.13 3.81 8.55

MV 44.89 9.78 34.16 3.00 10.73 50.77 9.04 42.98 3.71 7.79

Total 44.24 10.72 33.95 6.81 10.28 45.64 11.04 36.67 6.81 8.97

Table A2.8. Means and SDs of %Transition for V= [e], by Rate

Speaker

Rate 1 Rate 2




AA 48.77 14.14 30.62 2.67 18.15 38.91 9.66 24.79 9.58 14.12

AM 41.44 12.67 23.02 5.80 18.42 40.48 10.88 21.77 5.68 18.71

AN 48.55 9.63 26.04 6.59 22.51 48.54 13.90 35.45 3.52 13.09

CG 41.04 11.82 46.44 4.67 -5.40 43.65 14.09 34.71 2.02 8.94

DH 50.04 9.83 46.91 8.21 3.13 59.94 18.74 46.04 8.39 13.90

KR 63.63 20.13 41.98 4.18 21.65 41.73 17.82 37.74 4.36 3.99

LG 44.72 16.11 25.55 2.74 19.17 50.67 14.62 27.47 1.23 23.20

LL 50.06 10.03 30.74 2.42 19.32 46.31 10.04 41.05 4.61 5.26

MM 49.39 12.51 24.16 7.71 25.23 52.42 11.41 32.82 9.76 19.60

MV 43.06 10.85 25.18 3.08 17.88 47.42 16.62 33.13 4.98 14.29

Total 48.22 14.37 32.07 10.08 16.15 47.11 15.06 33.50 8.73 13.61

Table A2.9. Means and SDs of %Transition for V= [o], by Rate

Speaker

Rate 1 Rate 2




AA 44.22 5.82 30.38 3.06 13.84 48.93 6.57 27.29 2.90 21.64

AM 49.62 9.12 36.73 4.15 12.89 44.59 8.14 36.28 3.83 8.31

AN 54.06 15.37 30.11 7.16 23.95 46.12 14.59 34.22 1.22 11.90

CG 44.26 15.21 38.27 2.00 5.99 50.18 16.81 42.83 13.96 7.35

DH 55.47 11.00 40.93 11.56 14.54 55.14 15.06 42.23 4.46 12.91

KR 58.61 13.93 38.44 2.54 20.17 55.43 7.81 34.97 3.66 20.46

LG 51.66 13.04 29.78 4.10 21.88 51.24 13.70 33.57 4.57 17.67

LL 54.71 9.88 42.89 5.05 11.82 48.37 13.15 29.80 7.49 18.57

MM 59.95 10.04 53.46 4.86 6.49 61.46 26.40 42.29 8.06 19.17

MV 43.20 8.36 27.51 1.95 15.69 60.32 11.86 36.36 3.54 23.96

Total 51.58 12.41 36.85 8.82 14.73 52.07 14.54 35.98 7.34 16.09

250

Appendix 3: Tables of Individual Means and Standard Deviations (Chapter 4)

Table A3.1. Means and SDs of TB-TT Offset (raw values, in ms), by Rate

Speaker

Rate 1 Rate 2




AA 35.42 39.78 53.80 74.20 18.38 27.29 53.39 36.80 51.00 9.51

AM -16.35 59.07 -58.70 57.30 -42.35 16.00 40.00 -14.60 94.80 -30.60

AN 3.33 60.13 50.00 73.80 46.67 24.90 38.25 44.60 44.70 19.70

CG 43.90 83.20 68.33 32.29 24.43 1.59 52.52 -15.40 47.20 -16.99

DH 46.25 52.56 42.10 61.60 -4.15 24.17 49.11 63.33 14.20 39.16

KR 3.78 51.26 -0.42 87.10 -4.20 -2.08 40.00 -65.40 66.10 -63.32

LL -12.81 34.02 8.75 57.60 21.56 -18.85 37.08 -67.10 79.70 -48.25

MM 40.00 25.66 107.08 28.08 67.08 23.85 57.84 76.25 27.81 52.40

Total 17.85 58.07 33.85 76.10 16.00 12.22 48.75 7.00 77.38 -5.22

Table A3.2. Means and SDs of TB-TT Offset (absolute values, in ms), by Rate

Speaker

Rate 1 Rate 2




AA 40.63 34.33 75.40 49.50 34.77 42.50 42.04 55.00 27.57 12.50

AM 43.23 43.05 72.10 37.20 28.87 29.96 30.73 82.90 41.40 52.94

AN 37.29 46.97 84.17 20.98 46.88 34.69 29.45 54.58 30.34 19.89

CG 72.83 58.86 68.33 32.29 -4.50 41.82 31.16 46.25 12.45 4.43

DH 56.88 40.54 71.25 13.84 14.37 50.21 20.83 63.33 14.20 13.12

KR 34.67 37.59 72.90 42.20 38.23 25.00 31.08 76.30 51.90 51.30

LL 22.19 28.67 38.80 42.00 16.61 21.77 35.41 69.60 77.40 47.83

MM 40.00 25.66 107.08 28.08 67.08 47.19 40.65 76.25 27.81 29.06

Total 43.30 42.57 73.75 38.13 30.45 36.59 34.41 65.63 41.03 29.04

Table A3.3. Means and SDs of TB-TT Offset (absolute values, in ms), V= [a], by Rate

Speaker

Rate 1 Rate 2




AA 45.56 39.77 47.50 50.00 1.94 50.80 50.60 46.70 32.70 -4.10

AM 48.90 50.40 73.33 22.51 24.43 37.50 31.21 70.00 31.80 32.50

AN 34.44 34.34 85.80 26.00 51.36 38.61 32.35 59.20 29.90 20.59

CG 65.80 66.70 40.83 8.01 -24.97 42.22 24.39 40.00 12.65 -2.22

DH 48.06 12.85 61.67 13.29 13.61 53.06 16.64 57.50 12.94 4.44

KR 32.78 23.09 73.30 49.40 40.52 26.39 28.27 60.80 54.60 34.41

LL 25.56 31.90 70.00 38.60 44.44 30.00 43.90 81.70 85.70 51.70

MM 39.17 16.91 85.00 9.49 45.83 32.22 17.68 61.67 19.15 29.45

Total 42.53 39.17 67.19 32.89 24.66 38.85 33.02 59.69 40.45 20.84

251

Table A3.4. Means and SDs of TB-TT Offset (absolute values, in ms), V= [e], by Rate

Speaker

Rate 1 Rate 2




AA 37.86 23.80 128.30 17.60 90.44 39.76 24.72 85.00 0.00 45.24

AM 40.71 38.45 73.30 72.50 32.59 17.62 16.09 111.70 17.60 94.08

AN 26.90 37.53 91.70 18.90 64.80 34.76 30.35 53.30 40.70 18.54

CG 84.90 54.60 113.33 10.41 28.43 44.12 35.63 60.00 5.00 15.88

DH 74.30 53.60 81.67 5.77 7.37 49.05 19.40 78.33 12.58 29.28

KR 39.52 45.55 38.33 7.64 -1.19 28.81 38.57 118.33 11.55 89.52

LL 20.00 27.20 13.33 2.89 -6.67 16.67 31.68 106.70 79.70 90.03

MM 50.00 30.25 140.00 8.66 90.00 54.30 49.10 96.70 40.40 42.40

Total 46.08 44.23 85.00 47.57 38.92 35.43 34.12 88.91 38.43 53.48

Table A3.5. Means and SDs of TB-TT Offset (absolute values, in ms), V= [o], by Rate

Speaker

Rate 1 Rate 2




AA 37.20 45.40 78.30 18.90 41.10 32.20 55.80 51.67 2.89 19.47

AM 37.80 40.90 68.30 32.50 30.50 43.70 45.70 80.00 69.50 36.30

AN 67.20 75.00 73.33 10.41 6.13 26.67 21.51 46.70 31.80 20.03

CG 62.80 52.10 78.33 2.89 15.53 36.70 37.10 45.00 5.00 8.30

DH 33.89 23.42 80.00 5.00 46.11 47.20 31.40 60.00 8.66 12.80

KR 23.30 45.40 106.67 12.58 83.37 13.33 7.91 65.00 60.60 51.67

LL 20.56 27.89 1.67 2.89 -18.89 17.22 22.65 8.33 7.64 -8.89

MM 18.33 13.46 118.30 27.50 99.97 60.60 46.60 85.00 18.00 24.40

Total 38.26 45.34 75.63 36.13 37.37 34.69 37.89 55.21 37.31 20.52

Table A3.6. Means and SDs of Maximum TB Displacement (%), by Rate

Speaker

Rate 1 Rate 2




AA 99.75 1.73 99.85 0.51 0.10 99.87 0.61 100.00 0.00 0.13

AM 96.24 8.90 99.87 0.47 3.63 97.69 6.93 93.70 10.82 -3.99

AN 95.94 7.77 100.00 0.00 4.06 99.97 0.17 98.96 3.61 -1.01

CG 91.71 9.80 98.66 2.54 6.95 98.79 3.60 100.00 0.00 1.22

DH 98.31 6.94 99.98 0.06 1.67 97.38 8.54 100.00 0.00 2.62

KR 91.89 13.96 94.57 10.42 2.68 90.47 14.93 77.78 22.86 -12.69

LL 90.35 15.46 91.14 14.15 0.79 89.47 19.44 88.40 15.32 -1.07

MM 99.44 1.94 100.00 0.00 0.56 100.33 3.20 100.00 0.00 -0.33

Total 95.51 10.00 98.01 6.81 2.50 96.72 10.43 94.80 12.73 -1.92

252

Table A3.7. Means and SDs of Maximum TB Displacement (%), V= [a], by Rate

Speaker

Rate 1 Rate 2




AA 99.33 2.83 99.71 0.71 0.38 99.85 0.63 100.00 0.00 0.15

AM 98.03 3.24 99.73 0.66 1.70 94.23 10.54 91.40 13.99 -2.83

AN 91.48 10.43 100.00 0.00 8.52 99.91 0.28 97.92 5.10 -1.99

CG 88.75 11.05 97.88 3.29 9.13 98.24 5.12 100.00 0.00 1.76

DH 99.60 1.70 100.00 0.00 0.40 98.00 5.85 100.00 0.00 2.00

KR 95.68 8.78 90.02 13.61 -5.66 94.81 8.05 69.65 16.10 -25.16

LL 89.17 18.83 88.32 17.41 -0.85 94.22 13.38 96.11 4.88 1.89

MM 98.90 2.84 100.00 0.00 1.10 101.20 5.11 100.00 0.00 -1.20

Total 95.12 10.06 96.96 8.63 1.84 97.56 7.71 94.38 12.29 -3.18

Table A3.8. Means and SDs of Maximum TB Displacement (%), V= [e], by Rate

Speaker

Rate 1 Rate 2




AA 100.00 0.01 100.00 0.00 0.00 100.00 0.01 100.00 0.00 0.00

AM 98.76 4.09 100.00 0.00 1.24 99.68 1.08 100.00 0.00 0.33

AN 98.94 2.69 100.00 0.00 1.06 100.00 0.00 100.00 0.00 0.00

CG 95.56 6.16 100.00 0.00 4.44 99.57 1.39 100.00 0.00 0.43

DH 99.67 1.51 100.00 0.00 0.33 100.00 0.00 100.00 0.00 0.00

KR 93.35 12.80 98.27 2.83 4.92 85.77 19.21 95.20 5.20 9.43

LL 91.68 11.86 100.00 0.00 8.32 83.49 24.64 97.09 5.00 13.60

MM 99.66 1.24 100.00 0.00 0.34 99.74 0.92 100.00 0.00 0.26

Total 97.21 7.32 99.78 1.02 2.57 95.94 12.84 98.99 2.82 3.05

Table A3.9. Means and SDs of Maximum TB Displacement (%), V= [o], by Rate

Speaker

Rate 1 Rate 2




AA 100.00 0.00 100.00 0.00 0.00 99.63 1.11 100.00 0.00 0.37

AM 86.74 16.60 100.00 0.00 13.26 99.99 0.04 92.01 8.64 -7.98

AN 97.84 5.72 100.00 0.00 2.16 100.00 0.00 100.00 0.00 0.00

CG 89.94 11.48 98.87 1.96 8.93 98.38 2.78 100.00 0.00 1.62

DH 92.53 15.01 99.93 0.12 7.40 90.01 16.60 100.00 0.00 9.99

KR 75.37 20.26 99.97 0.06 24.60 92.77 11.96 76.60 39.30 -16.17

LL 89.59 17.04 87.93 13.61 -1.66 93.90 12.47 64.29 6.54 -29.61

MM 100.00 0.00 100.00 0.00 0.00 99.98 0.07 100.00 0.00 0.02

Total 92.20 13.91 98.34 5.72 6.14 96.83 8.94 91.61 17.81 -5.22

253

Table A3.10. Means and SDs of Maximum TT Displacement (%), by Rate

Speaker

Rate 1 Rate 2




AA 88.87 16.72 95.99 10.21 7.12 Mean SD 98.98 3.40 5.24

AM 74.59 21.56 83.44 13.64 8.85 93.74 10.90 90.62 13.18 9.16

AN 82.62 14.38 96.08 9.20 13.46 81.46 22.72 95.90 11.80 2.93

CG 81.48 21.58 93.46 12.50 11.98 92.97 15.07 93.44 8.44 1.14

DH 85.53 20.32 89.11 18.20 3.58 92.30 16.29 100.00 0.00 16.00

KR 94.55 8.36 98.93 1.95 4.38 84.00 25.05 99.26 2.56 3.43

LL 97.27 6.18 97.74 4.23 0.47 95.83 7.93 93.68 10.76 0.77

MM 89.23 14.89 94.40 9.49 5.17 92.91 15.69 100.00 0.00 9.47

Total 86.75 17.67 93.64 11.65 6.89 90.53 19.69 96.46 8.48 6.01

Table A3.11. Means and SDs of TT Displacement at Peak TB (%), by Rate

Speaker

Rate 1 Rate 2




AA 79.82 16.69 78.11 18.99 1.71 85.99 13.04 78.49 14.52 7.50

AM 62.41 24.31 53.27 7.89 9.14 73.68 27.63 64.59 22.81 9.09

AN 72.16 17.30 67.99 12.03 4.17 80.90 24.01 57.97 20.19 22.93

CG 57.95 27.02 55.55 17.74 2.40 68.88 27.19 60.13 23.88 8.75

DH 67.29 19.35 53.88 13.99 13.41 61.72 29.99 62.29 11.64 -0.57

KR 87.39 12.40 74.64 31.18 12.75 91.57 9.41 90.12 13.61 1.45

LL 95.36 7.40 95.28 6.17 0.08 92.19 15.36 91.09 9.87 1.10

MM 74.02 19.98 64.55 10.18 9.47 73.32 29.53 74.40 14.34 -1.08

Total 74.58 22.13 67.91 20.98 6.67 78.63 25.24 72.32 20.66 6.31

Table A3.12. Means and SDs of TT Displacement at Peak TB (%), V= [a], by Rate

Speaker

Rate 1 Rate 2




AA 77.64 20.15 75.90 26.30 1.74 85.26 14.20 78.65 20.14 6.61

AM 60.38 24.44 55.83 7.23 4.55 63.44 33.49 61.00 7.76 2.44

AN 60.82 12.70 61.08 12.26 -0.26 74.17 30.67 53.10 28.50 21.07

CG 52.67 24.26 66.89 19.08 -14.22 65.79 24.01 80.62 12.23 -14.83

DH 61.96 21.02 43.99 13.01 17.97 52.41 28.94 60.97 14.79 -8.56

KR 85.56 15.39 60.20 40.30 25.36 94.37 5.41 83.23 16.86 11.14

LL 96.02 7.83 92.80 7.82 3.22 96.06 8.11 95.57 4.80 0.49

MM 68.52 17.86 59.51 10.45 9.01 69.44 30.05 70.59 18.66 -1.15

Total 70.45 22.93 64.52 23.07 5.93 75.12 27.71 72.96 20.57 2.16

254

Table A3.13. Means and SDs of TT Displacement at Peak TB (%), V= [e], by Rate

Speaker

Rate 1 Rate 2




AA 79.74 12.9 74.23 8.81 5.51 85.87 11.96 75.77 2.05 10.10

AM 65.86 24.19 46.68 11.01 19.18 83.24 17.68 39.58 13.12 43.66

AN 80.46 12.51 69.83 3.16 10.63 87.69 15.19 62.36 6.75 25.33

CG 67.98 27.19 42.94 4.05 25.04 75.55 30.10 44.87 12.48 30.68

DH 66.84 18.16 66.12 4.78 0.72 61.29 29.45 66.55 8.92 -5.26

KR 88.47 10.39 91.47 1.54 -3.00 88.85 11.58 98.22 0.62 -9.37

LL 95.67 5.94 99.24 0.42 -3.57 88.55 20.11 96.94 3.61 -8.39

MM 69.76 20.21 64.07 6.68 5.69 71.40 32.64 79.24 8.52 -7.84

Total 77.01 20.09 69.32 19.29 7.69 80.42 23.79 70.21 22.21 10.21

Table A3.14. Means and SDs of TT Displacement at Peak TB (%), V= [o], by Rate

Speaker

Rate 1 Rate 2




AA 84.38 17.98 86.49 5.95 -2.11 87.75 14.41 79.98 5.19 7.77

AM 58.44 26.09 54.71 1.63 3.73 71.85 28.99 96.78 2.83 -24.93

AN 75.50 23.27 79.99 6.80 -4.49 78.50 24.12 63.39 4.67 15.11

CG 48.46 28.31 45.47 5.31 2.99 62.47 27.84 34.40 2.35 28.07

DH 78.98 14.76 61.40 5.29 17.58 81.37 26.60 60.68 9.06 20.69

KR 89.12 9.73 86.75 4.30 2.37 92.30 9.21 95.82 4.21 -3.52

LL 93.32 9.87 96.29 3.59 -2.97 92.95 12.89 76.30 5.07 16.65

MM 94.95 6.20 75.11 2.79 19.84 85.56 18.10 77.17 9.84 8.39

Total 77.41 24.02 73.28 17.37 4.13 81.59 22.65 73.07 20.07 8.52

255

Appendix 4: Hearing Screening (Chapter 5)

Hearing Screening/Prueba de audición

Date: _______________________________Participant code: _________________________

Por favor conteste las siguientes preguntas indicando con ‘’ la opción que corresponda:

1. ¿Tiene antecedentes de problemas del oído? (por ejemplo, infecciones , exceso de cera,

dolor, mucosidades) Sí / No

2. ¿Tiene un zumbido en los oídos? Sí / No

3. ¿Ha estado expuesta a ruidos fuertes en las últimas 24 horas? (por ejemplo, escuchar música

fuerte en el i-pod) Sí / No

4. ¿Ha estado expuesta a ruidos fuertes por períodos prolongados (meses/años)? Por ejemplo:

trabajar en un club/bar, trabajar en una fábrica ruidosa etc… Sí / No

5. ¿Ha tenido algún trastorno de aprendizaje o de desarrollo del habla, de la lectura o de la

escritura? Sí / No

Right Ear Left Ear

500 1000 2000 500 1000 2000

t

hre

shold

lev

el i

n d

B

-10

t

hre

shold

lev

el i

n d

B

-10

0 0

10 10

20 20

30 30

40 40

50 50

60 60

70 70

80 80

90 90

100 100

110 110

120 120

Pure Tone Average: Pure Tone Average:

_______________ = ______ dB _______________ = ______dB

3 3

256

Appendix 5: Handedness Questionnaire (Chapter 5)

Handedness Questionnaire/Cuestionario de preferencia manual

Date: _______________________________Participant code: _________________________

Indique la mano que utiliza normalmente para las siguientes 10 actividades marcando con ‘’ la

casilla correspondiende a cada columna. Por favor escriba una sola respuesta a cada pregunta.

¿Qué mano utiliza … ? Izquierda Derecha Ninguna preferencia (ambas)

1 para escribir

2 para dibujar

3 para cepillarse los dientes

4 para lanzar una pelota

5 para sujetar una cuchara

6 para peinarse el cabello

7 para afeitarse/maquillarse

8 para usar el mouse de la

computadora

9 para sujetar una raqueta

10 para cortar con tijeras

Totals:

(Scoring : L= -1,R = +1, B = 0)

Production and Perception of Vocalic Sequences in Mexican ......iii In support of the first and...

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Transcript of Production and Perception of Vocalic Sequences in Mexican ......iii In support of the first and...