Beyond the Phoneme A Juncture-Accent Model of Spoken Language Steven Greenberg, Hannah Carvey, Leah...

Beyond the PhonemeA Juncture-Accent Model of Spoken Language

Steven Greenberg, Hannah Carvey, Leah Hitchcock and Shuangyu ChangInternational Computer Science Institute1947 Center Street, Berkeley, CA 94704

{steveng, hmcarvey, leahh, shawnc}@icsi.berkeley.edu

Acknowledgements and Thanks

Research FundingU.S. Department of DefenseU.S. National Science Foundation

For Further Information

Consult the web site:

www.icsi.berkeley.edu/~steveng

OVERTURE

The Central Challenge for Models of Speech Recognition

The Serial Frame Perspective on SpeechTraditional models of speech recognition assume the identity of a phonetic segment is derived from

a detailed spectral profile of the acoustic signal computed for each time interval (frame) of speech

Phonemic Beads on a String Illustrated In traditional models of speech recognition words are represented as mere

sequences of phonetic segments (“phones”) ….

Phonemic Beads on a String Illustrated In traditional models of speech recognition words are represented as mere

sequences of phonetic segments (“phones”) ….

Strung together like “beads on a string”

Phonemic Beads on a String Illustrated In traditional models of speech recognition words are conceptualized as

mere sequences of phonetic segments (“phones”) ….

Strung together like “beads on a string”

No quarter is provided for stress accent or other syllabic properties

Language - The Traditional PerspectiveThe “classical” view of spoken language posits a quasi-arbitrary relation between

the lower and higher tiers of linguistic organization

Cat= [k] + [ae] + [t]

Cat = /k/ + /ae/ + /t/

ASR systems focus on decoding words from sequences of phones

A Challenge for the “Phonemic Beads on a String” Approach to Speech Recognition

Pronunciation Variability

Pronunciation Variability of Real SpeechPronunciation patterns encountered in everyday life are extremely diverse

Pronunciation Variability of Real SpeechPronunciation patterns encountered in everyday life are extremely diverse There are literally dozens of ways in which common words are pronounced

Pronunciation Variability of Real SpeechPronunciation patterns encountered in everyday life are extremely diverse There are literally dozens of ways in which common words are pronounced

(as the following two slides illustrate for the word “AND” based on manual phonetic annotation of a corpus comprising telephone dialogues)

How Many Pronunciations of “and”?

82 ae n63 eh n45 ix n35 ax n34 en30 n20 ae n dcl d17 ih n17 q ae n11 ae n d

7 q eh n7 ae nx6 ae ae n6 ah n5 eh nx4 uh n4 ix nx4 q ae n dcl d3 eh n d3 q ae nx

3 eh2 ae n dcl2 ae2 ax m2 ax n d2 ae eh n dcl d2 eh n dcl d2 ax nx2 q ae ae n2 q ix n2 ix n dcl d2 ih 2 eh eh n2 q eh nx2 ix d n1 eh m1 ax n dcl d1 aw n1 ae q1 eh dcl

N Pronunciation N Pronunciation

Canonical pronunciation

How Many Pronunciations of “and”?

1 ah nx1 ae n t1 eh d1 ah n dcl d1 ey ih n dcl1 ae ix n1 ae nx ax1 ax ng1 ay n1 ih ah n d1 ae hh1 ih ng1 ix1 ae n d dcl1 ix dcl d1 ae eh n1 hh n1 ix n t1 ae ax n dcl d1 iy eh n

1 m1 ae ae n d1 nx1 q ae ae n1 q ae ae n dcl d1 q ae eh n dcl d1 q ae ih n1 aa n1 q ae n d1 ? nx1 q ae n q1 eh n m1 q eh en dcl1 eh ng1 q eh n q1 em1 q eh ow m1 q ih n1 q ix en1 er

N Pronunciation N Pronunciation

Pronunciation Variability of Real SpeechThe are literally dozens of ways in which common words are pronounced

And as the following slide illustrates for the 20 most frequent words from the same corpus (Switchboard)

Pronunciation Variability of Real SpeechThe are literally dozens of ways in which common words are pronounced

And as the following slide illustrates for the 20 most frequent words from the same corpus (Switchboard)

(which together account for 35% of the word tokens in the corpus)

1 I 6 4 9 5 3 5 3 a y

2 a n d 5 2 1 8 7 1 6 a e n

3 th e 4 7 5 7 6 2 7 d h a x

4 y o u 4 0 6 6 8 2 0 y ix

5 th a t 3 2 8 1 1 7 1 1 d h a e

6 a 3 1 9 2 8 6 4 a x

7 to 2 8 8 6 6 1 4 tc l t u w

8 k n o w 2 4 9 3 4 5 6 n o w

9 o f 2 4 2 4 4 2 1 a x v

1 0 it 2 4 0 4 9 2 2 ih

1 1 y e a h 2 0 3 4 8 4 3 y a e

1 2 in 1 7 8 2 2 4 5 ih n

1 3 th e y 1 5 2 2 8 6 0 d h e y

1 4 d o 1 3 1 3 0 5 4 d c l d u w

1 5 s o 1 3 0 1 4 7 4 s o w

1 6 b u t 1 2 3 4 5 1 2 b c l b a h tc l t

1 7 is 1 2 0 2 4 5 0 ih z

1 8 lik e 1 1 9 1 9 4 6 l a y k c l k

1 9 h a v e 1 1 6 2 2 5 4 h h a e v

2 0 w a s 1 1 1 2 4 2 3 w a h z

2 1 w e 1 0 8 1 3 8 3 w iy

2 2 it's 1 0 1 1 4 2 0 ih tc l s

2 3 ju s t 1 0 1 3 4 1 7 jh ix s

2 4 o n 9 8 1 8 4 9 a a n

2 5 o r 9 4 2 3 3 6 e r

2 6 n o t 9 2 2 4 2 4 m a a q

2 7 th in k 9 2 2 3 3 2 th ih n g k c l k

2 8 fo r 8 7 1 9 4 6 f e r

2 9 w e ll 8 4 4 9 2 3 w e h l

3 0 w h a t 8 2 4 0 1 4 w a h d x

3 1 a b o u t 7 7 4 6 1 2 a x b c l b a w

3 2 a ll 7 4 2 7 2 4 a o l

3 3 th a t's 7 4 1 9 1 6 d h e h s

3 4 o h 7 4 1 7 6 1 o w

3 5 re a lly 7 1 2 5 4 5 r ih l iy

3 6 o n e 6 9 8 7 8 w a h n

3 7 a re 6 8 1 9 4 2 e r

3 8 I'm 6 7 9 2 6 q a a m

3 9 rig h t 6 1 2 1 2 8 r a y

4 0 u h 6 0 1 6 4 1 a h

4 1 th e m 6 0 1 8 2 3 a x m

4 2 a t 5 9 3 6 8 a e d x

4 3 th e re 5 8 2 8 2 2 d h e h r

4 4 my 5 8 9 6 6 m a y

4 5 me a n 5 6 1 0 5 8 m iy n

4 6 d o n 't 5 6 2 1 1 4 d x o w

4 7 n o 5 5 8 7 7 n o w

4 8 w ith 5 5 2 0 3 5 w ih th

4 9 if 5 5 1 8 4 1 ih f

5 0 w h e n 5 4 1 8 3 1 w e h n

5 1 c a n 5 4 2 8 1 5 k c l k a e n

5 2 th e n 5 1 1 9 3 8 d h e h n

5 3 b e 5 0 1 1 7 6 b c l b iy

5 4 a s 4 9 1 6 1 8 a e z

5 5 o u t 4 7 1 9 2 2 a e d x

5 6 k in d 4 7 1 7 2 1 k c l k a x n x

5 7 b e c a u e 4 6 3 1 1 5 k c l k a x z

5 8 p e o p le 4 5 2 1 4 4 p c l p iy p c l l e l

5 9 g o 4 5 5 8 3 g c l g o w

6 0 g o t 4 5 3 2 1 5 g c l g a a

6 1 th is 4 4 1 1 4 7 d h ih s

6 2 s o me 4 3 4 4 8 s a h m

6 3 w o u ld 4 1 1 6 2 9 w ih d c l

6 4 th in g s 4 1 1 5 5 2 th ih n g z

6 5 n o w 3 9 1 1 6 9 n a w

6 6 lo t 3 9 9 4 7 l a a d x

6 7 h a d 3 9 1 9 2 4 h h a e d c l

6 8 h o w 3 9 1 1 5 3 h h a w

6 9 g o o d 3 8 1 3 2 7 g c l g u h d c l

7 0 g e t 3 8 2 0 1 3 g c l g e h d x

7 1 s e e 3 7 6 8 0 s iy

7 2 fro m 3 6 1 0 2 8 f r a h m

7 3 h e 3 6 7 3 9 iy

7 4 me 3 5 5 8 7 m iy

7 5 d o n 't 3 5 2 1 1 4 d x o w

7 6 th e ir 3 3 1 9 2 5 d h e h r

7 7 mo re 3 2 1 1 5 6 m a o r

7 8 it's 3 1 1 4 2 0 ih tc l s

7 9 th a t's 3 1 2 0 1 6 d h e h s

8 0 to o 3 1 6 6 0 tc l t u w

8 1 o k a y 3 1 1 7 4 5 o w k c l k e y

8 2 v e ry 3 0 1 1 3 6 v e h r iy

8 3 u p 3 0 1 1 3 4 a h p c l p

8 4 b e e n 3 0 1 1 5 1 b c l b ih n

8 5 g u e s s 2 9 8 4 2 g c l g e h s

8 6 time 2 9 8 6 2 tc l t a y m

8 7 g o in g 2 9 2 1 1 3 g c l g o w ih n g

8 8 in to 2 8 2 0 1 4 ih n tc l t u w

8 9 th o s e 2 7 1 2 4 2 d h o w z

9 0 h e re 2 7 1 1 2 5 h h iy e r

9 1 d id 2 7 1 3 2 3 d c l d ih d x

9 2 w o rk 2 5 8 6 6 w e r k c l k

9 3 o th e r 2 5 1 4 2 6 a h d h e r

9 4 a n 2 5 1 2 2 8 a x n

9 5 I'v e 2 5 7 4 6 a y v

9 6 th in g 2 4 9 5 2 th ih n g

9 7 e v e n 2 4 7 4 0 iy v ix n

9 8 o u r 2 3 9 3 3 a a r

9 9 a n y 2 3 1 1 2 3 ix n iy

1 0 0 w e 're 2 3 8 2 5 w e y r

How Many Different Pronunciations?

1 I 649 53 53 ay2 and 521 87 16 ae n3 the 475 76 27 dh ax4 you 406 68 20 y ix5 that 328 117 11 dh ae6 a 319 28 64 ax7 to 288 66 14 tcl t uw8 know 249 34 56 n ow9 of 242 44 21 ax v

10 it 240 49 22 ih11 yeah 203 48 43 y ae12 in 178 22 45 ih n13 they 152 28 60 dh ey14 do 131 30 54 dcl d uw15 so 130 14 74 s ow16 but 123 45 12 bcl b ah tcl t17 is 120 24 50 ih z18 like 119 19 46 l ay kcl k19 have 116 22 54 hh ae v20 was 111 24 23 w ah z

Rank Word N #PronMost CommonPronunciation

MCP%Total

The 20 most frequency words account for 35% of the tokens

QUESTION

How do listeners decode the speech signal given the large amount of

pronunciation variation?

PART ONE

Anatomy of a Syllable

Language - A Syllable-Centric PerspectiveA more empirically grounded perspective of spoken language focuses on the

SYLLABLE as the interface between “sound” and “meaning”

Within this framework the relationship between the syllable and the higher and lower tiers is non-arbitrary and systematic statistically

The Importance of the Syllable The analyses to follow are all linked, in some fashion, to syllable structure


In order to highlight patterns germane to variation in segmental duration it is necessary to partition the data in terms of syllable position


In order to highlight patterns germane to variation in segmental duration it is necessary to partition the data in terms of syllable position (as well as stress accent level)



As a consequence, we will examine the onsets, codas and nuclei of syllables separately in order to gain insight into the underlying patterns




What is an onset?




What is a onset? What is a nucleus?




What is a onset? What is a nucleus? What is a coda?




What is an onset? What is a nucleus? What is a coda?

The following slides provide a brief (and gentle) introduction to syllable structure

Syllable and Phonetic Segment Illustrated Syllables generally consist of three constituents - ONSET, NUCLEUS, CODA

“J” = JUNCTUREOGI Numbers95 corpus


Virtually all syllables contain a NUCLEUS, which is VOCALIC (by definition)




Most (but not all) syllables also contain an ONSET (usually a CONSONANT)





Many syllables contain a CODA (also typically a CONSONANT)






The most common syllable form in English is Onset + Nucleus + Coda (“Nine”)







Followed in popularity by Onset + Nucleus (“Two”)







Followed in popularity by Onset + Nucleus (“Two”)

Onset segments often differ in significant ways from coda segments


PART TWO

Spectro-Temporal Profiles

The Spectro-Temporal Profile (STeP)Certain specific (and important) properties of the syllable are not well

represented in terms of the traditional 2.5-D spectrographic representation



STRESS ACCENT and JUNCTURE are two such properties



Stress Accent and Juncture are two such properties

A different representation, based on the log, critical-band energy profile across frequency and time, can provide the requisite detail





As shown in “miniature” below …..





As shown in “miniature” below …..

STePs are derived from averages of hundreds of individual instances

The Spectro-Temporal Profile (STeP)Certain specific (and important) properties of the syllable are not well represented in terms of

the traditional 2.5-D spectrographic representation



As shown in “miniature” below ….

(and as shown in expanded form on the following slides)

STePs are derived from averages of hundreds of individual instances

Spectro-Temporal Profile - DiSyllabic Word

[s]

[eh]

[vx]

[en]

juncture accented syllable

unaccented syllable

“Seven”

mean duration

Full-spectrumperspective

OGI Numbers95

[s] [eh] [vx] [en]

[s]

[eh]

[vx][en]

juncture accented syllable

unaccented syllable

mean duration

“Seven” High-frequency

perspective

OGI Numbers95

[s] [eh] [vx] [en]

Spectro-Temporal Profile - DiSyllabic Word

PART THREE

Scientific Approach to Speech Recognition

Ascertain the contribution of ….

A Scientific Approach to Speech Recognition

Ascertain the contribution of ….(1) phonetic segment (and feature) classification


Ascertain the contribution of ….(1) phonetic segment (and feature) classification(2) phonetic segmentation


Ascertain the contribution of ….(1) phonetic segment (and feature) classification(2) phonetic segmentation(3) stress accent, and


Ascertain the contribution of ….(1) phonetic segment (and feature) classification(2) phonetic segmentation(3) stress accent, and (4) syllable position


Ascertain the contribution of ….(1) phonetic segment (and feature) classification(2) phonetic segmentation(3) stress accent, and (4) syllable position to ASR performance



Using the OGI Numbers95 Corpus as a controlled (limited vocabulary) corpus




And a relatively transparent recognition engine utilizing the following variety of articulatory-based features: manner and place of articulation, voicing, vowel height, lip-rounding, spectral dynamics, segment length





That are explicitly tied to syllable position (i.e., onset, nucleus and coda) and stress-accent level





That are explicitly tied to syllable position (i.e., onset, nucleus and coda) and stress-accent level

We will be comparing the “baseline” system (entirely automatic recognition) with an entirely “fabricated” set of input data (derived from hand-labeled phonetic annotation + autoSAL) as well as a “half-way house” system that is partially automatic and partially not (manually derived phonetic segmentation, as well as whether each segment is vocalic or not)


Entirely Stress-Accent Dependent ResultsWord Error Rate

Fabricated 1.3%Half-way House 2.0% Baseline 5.6%

Numbers95 Recognition – Stress Accent Impact



The half-way house system is much closer in performance to the fabricated data version than to the baseline system, suggesting that ….





Accurate phonetic segmentation is extremely important for enhanced ASR performance, as is knowledge of the location of the syllabic nucleus






Stress-accent information most important for the vocalic nucleus – without it WER increases by 10-20%






Stress-accent information most important for the vocalic nucleus – without it WER increases by 10-20%

Also important for coda – WER increases by 7-15%


Effect of pronunciation variation as a function of syllable position, where the “canonical” pronunciation is potentially fixed for each syllable position separately (or “All” together)

“Standard” refers to regular recognition system

Word Error Rate Standard Onset Nucleus Coda All

Fabricated 1.29 1.33 1.61 1.63 1.76%Half-way House 1.97 2.16 2.21 2.55 2.81%Baseline 5.59 5.91 5.91 6.70 7.03%

Numbers95 Recognition – Pronunciation Impact





Conclusions:

Onset segments are most canonical






Conclusions:


Coda segments are least canonical






Conclusions:


Coda segments are least canonical

Therefore, it is important to provide for pronunciation variation in ASR system


Effect of pronunciation variation as a function of syllable position, where each syllabic constituent is “neutralized” with respect to lexical matching (i.e., each element is factored out of the decoding process separately)

“Standard” refers to the regular recognition system

Word Error Rate Standard Onset Nucleus Coda

Fabricated 1.29 9.70 5.95 3.92%Half-way House 1.97 11.27 13.28 6.60%Baseline 5.59 15.70 20.22 10.13%

Numbers95 – Syllable Position Importance





Neutralization of the onset and nucleic elements exerts a greater impact on ASR performance than codas






Neutralization of the onset and nucleic elements exerts a greater impact on ASR performance than codas

Conclusion:Onsets and nuclei are most important for lexical access in an ASR system

(at least for the Numbers95 corpus)


PART FOUR

Being Phonetically and Prosodically Annotated

Phonetic Transcription of Spontaneous EnglishTelephone dialogues of 5-10 minutes duration, from the SWITCHBOARD

corpus, have been phonetically annotated (labeled and segmented)

Phonetic Transcription of Spontaneous EnglishTelephone dialogues of 5-10 minutes duration, from the SWITCHBOARD

corpus, have been phonetically transcribed (labeled and segmented)

Most of this material has been annotated manually

Phonetic Transcription of Spontaneous EnglishTelephone Dialogues of 5-10 minutes duration, from the SWITCHBOARD


Most of this material has been annotated manually 4 hours labeled at the phone level and segmented at the syllabic level



Most of this material has been annotated manually 4 hours labeled at the phone level and segmented at the syllabic level 1 hour labeled and segmented at the phonetic-segment level



Most of this material has been annotated manually 4 hours labeled at the phone level and segmented at the syllabic level 1 hour labeled and segmented at the phonetic-segment levelThe remaining material segmented at the phonetic-segment level using automatic

methods




methods45 minutes of hand-labeled stress-accent material




methods45 minutes of hand-labeled stress-accent materialAn additional four hours of stress-accent material automatically labeled (though

unused in the current analysis)






There is a Lot of Diversity in the Material Transcribed






There is a Lot of Diversity in the Material TranscribedSpans speech of both genders (ca. 50/50%), reflecting a wide range of American

dialectal variation, speaking rate and voice quality






There is a Lot of Diversity in the Material TranscribedSpans speech of both genders (ca. 50/50%), reflecting a wide range of American

dialectal variation, speaking rate and voice quality

Transcription SystemA variant of Arpabet, with phonetic diacritics such as:_gl,_cr, _fr, _n, _vl, _vd

Phonetic Transcription of Spontaneous EnglishThe Data are Available at ….

Phonetic Transcription of Spontaneous EnglishThe Data are Available at ….

http://www.icsi/berkeley.edu/real/stp

Annotation of Stress AccentForty-five minutes of the phonetically annotated portion of the Switchboard

corpus was manually labeled with respect to stress accent



Three levels of accent were distinguished:




Heavy




Heavy Light




Heavy Light None




Heavy Light None

(In actuality, labelers assigned a “1” to fully accented syllables, a “null” to completely unaccented syllables, and a “0.5” to all others)




Heavy Light None


An example of the annotation (attached to the vocalic nucleus) is shown below (where the accent levels could not be derived from a dictionary)




Heavy Light None



In this example most of the syllables are unaccented, with two labeled as lightly accented (0.5)




Heavy Light None



In this example most of the syllables are unaccented, with two labeled as lightly accented (0.5) (and one other labeled as very lightly accented (0.25))

The data are available at ….

Annotation of Stress Accent

The data are available at ….

http://www.icsi/berkeley.edu/~steveng/prosody

Annotation of Stress Accent

Automatic Labeling of Stress AccentThis forty-five minutes of hand-labeled phonetic and prosodic annotation

from the Switchboard corpus was used as training data for development of an Automatic Stress Accent Labeling System (AutoSAL)

How Good is AutoSAL?There is an 79% concordance between human and machine accent labels

when the tolerance level is a quarter-step



There is 97.5% concordance when the tolerance level is half a step



There is 97.5% concordance when the tolerance level is half a step

This degree of concordance is as high as that exhibited by two highly trained (human) transcribers

PART FIVE

Stress Accent and Syllable Position

The Importance of Syllable StructureBefore going into the details of durational variation at the segmental level

we briefly examine some general patterns of pronunciation variation that are conditioned by syllable position and stress accent

The Importance of Syllable StructureBefore going into the details of durational variation at the segmental level

we briefly examine some general patterns of pronunciation variation that are conditioned by syllable position and stress accent

These data serve to illustrate the sort of variation observed that is conditioned by position within the syllable

All Segments

Pronunciation Variation – Syllable and Accent

Deletions

InsertionsSubstitutions

Pronunciation variation is systematic at the level of the syllable

CODATerritory

ONSETTerritory

NUCLEUSTerritory

All Segments

Pronunciation Variation – Syllable and Accent

Deletions


Pronunciation variation is systematic at the level of the syllable

Particularly when stress accent is also taken into account

CODATerritory

ONSETTerritory

NUCLEUSTerritory

Pronunciation Variation – Syllable and Accent Pronunciation variation is systematic at the level of the syllable

Particularly when stress accent is also taken into account

BOTH syllable structure and accent level are required for a full accounting

All Segments Deletions


CODATerritory

ONSETTerritory

NUCLEUSTerritory

PART SIX

Durational Properties of

Pronunciation Variation

Analysis of Durational Properties of SpeechThe following analyses are conditioned on stress accent level and (for the

most part) syllable position



We’ll begin with analyses illustrating the patterns associated with three levels of stress accent (heavy, light and none) to show the graded nature of the durational properties pertaining to syllable and segment duration




However, for purposes of illustrative clarity, many of the slides will show only two levels of accent (heavy and none) in order to delineate the differences in duration associated with stress accent level




However, for purposes of illustrative clarity, many of the slides will show only two levels of accent (heavy and none) in order to delineate the differences in duration associated with stress accent level

Under such conditions, the durational properties associated with light accent are generally intermediate between heavy accent and none

Syllable Duration - Across Syllable FormsThere is a broad range of syllable structures observed in spoken English


The CV and CVC forms cover ca. 60% of the syllables

V = VowelC = Consonant



Together, the V, VC, CV and CVC forms account for 85% of syllables




Together, the V, VC, CV and CVC forms account for 85% of syllables

The CVCC and CCVC (complex syllable) forms account for another 10%


Syllable Duration - Across Syllable FormsIt is unsurprising that syllable duration is largely a function of the number of

segments within the syllable (as shown in the graph below)

Canonical Syllable Forms




Note the systematic lengthening of the syllable for each form as the accent level increases from “NONE” to “LIGHT “to “HEAVY”






This pattern is representative of accent’s impact on duration






This pattern is representative of accent’s impact on duration (as we’ll see)



Syllable Duration - Accent Level/Syllable Form


This graph shows the same data as the previous slides, but from the perspective of just two accent levels (“HEAVY” and “NONE”)





The heavily accented syllables are generally 60-100% longer than their unaccented counterparts






The disparity in duration is most pronounced for syllable forms with one or no consonants (i.e., V, VC, CV)






The disparity in duration is most pronounced for syllable forms with one or no consonants (i.e., V, VC, CV)

This pattern implies that accent has the greatest impact on vocalic duration



Nucleus Duration - Accent Level/Syllable FormThe hypothesis delineated on the previous slide (that accent has the most

profound impact on vocalic duration) is confirmed in the graph below




Vowels in accented syllables (of all forms) are at least twice as long as their unaccented counterparts




Vowels in accented syllables (of all forms) are at least twice as long as their unaccented counterparts

This pattern implies that the syllable nucleus absorbs a major component of accent’s impact (at least as far as duration is concerned)

PART SEVEN

Stress Accent and the Vocalic Nucleus

Because the pattern of stress accent’s impact on vocalic duration is relatively uniform across syllable form it is likely that the specific structure of the syllable has relatively little impact on vocalic duration

Stress Accent’s Impact on the Vocalic Nucleus


As a consequence, the remaining analyses pertaining to accent’s impact on vocalic duration collapse the data across syllable form



As a consequence, the remaining analyses pertaining to accent’s impact on vocalic duration collapse the data across syllable form

We now examine vocalic duration in somewhat greater detail and illustrate how duration, stress accent and vocalic identity interact


The Spatial Patterning

of Duration in Vocalic Nuclei

Vowel quality is generally thought to be a function primarily of two articulatory properties – both related to the motion of the tongue

A Brief Primer on Vocalic Acoustics


• The front-back plane is most closely associated with the second formant frequency (or more precisely F2 - F1) and the volume of the front-cavity resonance




• The height parameter is closely linked to the frequency of F1




• The height parameter is closely linked to the frequency of F1

In the classic vowel “triangle,” segments are positioned in terms of the tongue positions associated with their production, as follows:


In the following slides duration is plotted on a 2-D grid, where the x-axis represents the (hypothetical) front-back tongue position

Spatial Patterning of Duration et al.

In the following slides duration is plotted on a 2-D grid, where the x-axis represents the (hypothetical) front-back tongue position (and hence remains a constant throughout the plots to follow)


In the following slides duration is plotted on a 2-D grid, where the x-axis represents the (hypothetical) front-back tongue position (and hence remains a constant throughout the plots to follow)

The y-axis serves as the dependent measure, expressed in terms of either duration or the proportion of fully stressed (or unstressed) nuclei


Vocalic Duration and Vowel HeightThe spatial patterning of vocalic segments is systematic with respect to

duration

Vocalic Duration and Vowel HeightThe spatial patterning of vocalic segments is systematic with respect to

duration

Low vowels, be they diphthongs or monophthongs, are longer (on average) than high vowels

Vocalic Duration and Vowel Height

All nuclei Diphthongs Monophthongs

The spatial patterning of vocalic segments is systematic with respect to duration






Thus, duration appears to be highly correlated with vowel height





Thus, duration appears to be highly correlated with vowel height

But … the situation is a little more complicated than first appearances would suggest

Durational Differences - Stressed/UnstressedThere is a large dynamic range in duration between accented and unaccented

vocalic nuclei


Durational Differences - Stressed/UnstressedThere is a large dynamic range in duration between accented and unaccented vocalic nuclei

Moreover, diphthongs and tense, low monophthongs tend to exhibit a larger dynamic range than the lax monophthongs


Durational Differences - Stressed/UnstressedThere is a large dynamic range in duration between accented and unaccented vocalic nuclei

Moreover, diphthongs and tense, low monophthongs tend to exhibit a larger dynamic range than the lax monophthongs


Lax monophthongs

Vocalic Identity Among Unstressed NucleiThe high, lax monophthongs are almost always unstressed


The low vowels, be they monophthongs or diphthongs, are rarely unstressed


The low vowels, be they monophthongs or diphthongs, are rarely unstressed

The high diphthongs and high/mid, tense monophthongs occupy an intermediate position

The high vowels are rarely fully stressed

Vocalic Identity Among Fully Stressed Nuclei


The low vowels, be they monophthongs or diphthongs, are far more likely to be fully stressed




An intermediate degree of stress accounts for the other vocalic instances




An intermediate degree of stress accounts for the other vocalic instances (but will not be addressed here)


The vowels of heavily accented syllables are (mostly) pronounced canonically

Canonical Pronunciations Non-Canonical Pronunciations

Vocalic Variation – Importance of Stress Accent


Low vowels are largely the province of accented syllables




Low vowels are largely the province of accented syllables, and

High vowels the province of unaccented syllables






Moreover, there’s a lexical bias towards high vowels for unaccented forms






Moreover, there’s a lexical bias towards high vowels for unaccented forms

That’s reinforced in patterns of deviation from canonical pronunciation



Vocalic Height Deviation from Canonical

Amount of Change Direction of Change

Vowels are more likely to RISE in height than to descend when unaccented




Vocalic lowering of height is rare





Most deviations from the canonical maintain vowel height






More than a single height step deviation is uncommon






More than a single height step deviation is uncommon

Virtually all 2-step height deviations occur in unaccented syllables

The Vowel Space Under (Full) Stress (Accent) In unaccented nuclei there is a relatively even distribution of segments

across the vowel space, with a slight bias towards the front and central vowels

Canonical Vowels Only

In unaccented syllables vowels are confined largely to the high-front and high-central sectors of the articulatory space

The Vowel Space Without (Stress) Accent


In unaccented syllables vowels are confined largely to the high-front and high-central sectors of the articulatory space

The low and mid vowels “get creamed”

The Vowel Space Without (Stress) Accent


Stress accent exerts a profound effect on the character of the vowel space

The Vowel Spaces Compared

Heavily Accented Unaccented



High vowels are largely associated with unaccented syllables






Low vowels are mostly associated with accented forms






Low vowels are mostly associated with accented forms

This distinction between accented and unaccented syllables is of profound importance for understanding (and modeling) pronunciation variation




Duration appears to play an important (but certainly not exclusive) role in stress accent for spontaneous American English discourse

Is It Stress? Vocalic Identity? Or What?


For any given vocalic class, stressed segments are longer (on average)



For any given vocalic class, stressed segments are longer (on average)The durational disparity is most pronounced among the low vowels and the

diphthongs




diphthongs

Low vowels tend to be much longer in duration than high vowels




diphthongs

Low vowels tend to be much longer in duration than high vowelsThis is the case even for diphthongs




diphthongs


Low vowels are rarely without some measure of stress accent




diphthongs


Low vowels are rarely without some measure of stress accentThis is true for monophthongs as well as diphthongs




diphthongs



High vowels are RARELY fully stressed




diphthongs



High vowels are RARELY fully stressedThis is particularly so for monophthongs, but also applies to diphthongs




diphthongs



High vowels are RARELY fully stressedThis is particularly so for monophthongs, but also applies to diphthongs

Thus, stress accent appears to be intricately involved with vocalic identity


PART EIGHT

Stress Accent’s Impact on Syllable Onsets

Stress Accent and Syllable OnsetsThe onset is often cited as the key syllabic constituent with respect to

“lexical access”



It is therefore of interest to ascertain how the onset’s duration behaves as a function of accent level




Because of the onset’s key role in lexical access one might assume that its duration would be relatively stable across accent level





The following slides suggest that this assumption is INCORRECT





The following slides suggest that this assumption is INCORRECT,

And that the structure of the onset is more complex (and more interesting) than initial intuition would suggest


Onset Duration - Accent Level/Syllable FormThe duration of the syllable onset varies significantly as a function of accent

level (though not quite as much as exhibited by vocalic constituents)




Onset duration is similar across syllable form




Onset duration is similar across syllable form (except that segments comprising complex onsets [i.e., CCVC] are slightly shorter)


Onset Duration - Accent Level/Syllable FormThe duration of the syllable onset varies significantly as a function of accent level (though not

quite as much as exhibited by vocalic constituents)

Onset duration is similar across syllable form (except that segments comprising complex onsets [i.e., CCVC] are slightly shorter)

The duration of unaccented onsets is similar across syllable forms


Onset Duration - Accent Level/Syllable FormOnsets of accented syllables are generally 50-60% longer than their

unaccented counterparts


Onset Duration - Accent Level/Syllable FormOnsets of accented syllables are generally 50-60% longer than their

unaccented counterparts

Although this durational difference is not quite as large as observed for vocalic nuclei, it is still substantial (and mostly consistent across forms)

Place of Articulation – A Brief PrimerThe tongue contacts (or nearly so) the roof of the mouth in producing many of the consonantal sounds in English

AnteriorLabial [p] [b] [m]Labio-dental [f] [v] Inter-dental [th] [dh]

CentralAlveolar [t] [d] [n] [s] [z]

PosteriorPalatal [sh] [zh]Velar [k] [g] [ng]

From Daniloff (1973)

Segmental Identity and Stress AccentIt is of interest to compare accent’s impact on segmental duration with its

impact on segmental realization (i.e., whether the segment is realized canonically or not …)


impact on segmental realization (i.e., whether the segment is realized canonically or not …)

Usually, non-canonical realizations are manifest as segmental deletions


impact on segmental realization (i.e., whether the segment is realized canonically or not ... )


The pattern of segmental realization bears some correspondence to durational variation as a function of accent level





But also exhibits some interesting differences





But also exhibits some interesting differences(which are potentially significant for models of phonetic organization)





But also exhibits some interesting differences(which are potentially significant for models of phonetic organization)

Before we examine the segmental patterns in detail, a brief primer on the interpretation of these data is presented

Road Map - How to Interpret the Data

Accent

Segment Can Trans Can Trans Can Trans Can Trans

p 203 205 153 153 94 94 450 452

b 126 127 227 225 214 190 567 542

m 137 137 211 211 116 110 464 458

f 136 136 104 104 113 103 353 343

v 35 33 58 58 108 93 201 184

th 62 61 102 100 28 26 192 187

TotalHeavy Light None

dh 95 80 311 257 625 451 1031 788

y 63 72 135 136 193 145 391 353

Compare the numbers in the YELLOW and ORANGE columns

Can = Canonical formTrans = Transcribed (i.e., phonetically realized)


Accent


p 203 205 153 153 94 94 450 452

b 126 127 227 225 214 190 567 542

m 137 137 211 211 116 110 464 458

f 136 136 104 104 113 103 353 343

v 35 33 58 58 108 93 201 184

th 62 61 102 100 28 26 192 187


dh 95 80 311 257 625 451 1031 788

y 63 72 135 136 193 145 391 353


Most numbers in the YELLOW / ORANGE columns will be similar



Accent


p 203 205 153 153 94 94 450 452

b 126 127 227 225 214 190 567 542

m 137 137 211 211 116 110 464 458

f 136 136 104 104 113 103 353 343

v 35 33 58 58 108 93 201 184

th 62 61 102 100 28 26 192 187


dh 95 80 311 257 625 451 1031 788

y 63 72 135 136 193 145 391 353



Indicating that the phonetic realization of the segment is the canonical form



Accent


p 203 205 153 153 94 94 450 452

b 126 127 227 225 214 190 567 542

m 137 137 211 211 116 110 464 458

f 136 136 104 104 113 103 353 343

v 35 33 58 58 108 93 201 184

th 62 61 102 100 28 26 192 187


dh 95 80 311 257 625 451 1031 788

y 63 72 135 136 193 145 391 353




A large disparity between columns is marked with a blue box



Accent


p 203 205 153 153 94 94 450 452

b 126 127 227 225 214 190 567 542

m 137 137 211 211 116 110 464 458

f 136 136 104 104 113 103 353 343

v 35 33 58 58 108 93 201 184

th 62 61 102 100 28 26 192 187


dh 95 80 311 257 625 451 1031 788

y 63 72 135 136 193 145 391 353





READY?



Accent


p 203 205 153 153 94 94 450 452

b 126 127 227 225 214 190 567 542

m 137 137 211 211 116 110 464 458

f 136 136 104 104 113 103 353 343

v 35 33 58 58 108 93 201 184

th 62 61 102 100 28 26 192 187


dh 95 80 311 257 625 451 1031 788

y 63 72 135 136 193 145 391 353





READY? OK, Let’s go!


Syllable Onset Statistics – ANTERIOR Place

Accent


p 203 205 153 153 94 94 450 452

b 126 127 227 225 214 190 567 542

m 137 137 211 211 116 110 464 458

f 136 136 104 104 113 103 353 343

v 35 33 58 58 108 93 201 184

th 62 61 102 100 28 26 192 187


dh 95 80 311 257 625 451 1031 788

y 63 72 135 136 193 145 391 353

Stress accent has relatively little impact on anterior onset segments



Accent


p 203 205 153 153 94 94 450 452

b 126 127 227 225 214 190 567 542

m 137 137 211 211 116 110 464 458

f 136 136 104 104 113 103 353 343

v 35 33 58 58 108 93 201 184

th 62 61 102 100 28 26 192 187


dh 95 80 311 257 625 451 1031 788

y 63 72 135 136 193 145 391 353


EXCEPT for [dh] and [y]



Accent


p 203 205 153 153 94 94 450 452

b 126 127 227 225 214 190 567 542

m 137 137 211 211 116 110 464 458

f 136 136 104 104 113 103 353 343

v 35 33 58 58 108 93 201 184

th 62 61 102 100 28 26 192 187


dh 95 80 311 257 625 451 1031 788

y 63 72 135 136 193 145 391 353


EXCEPT for [dh] and [y]

[dh] (as in “the” and “them”) tends to delete in unaccented syllables, as does [y] (although to a lesser extent)


Accent


t 241 245 276 230 513 276 1030 751

d 141 143 149 134 173 128 463 405

dx 0 3 0 62 0 179 0 244

n 133 135 237 196 194 130 564 461

nx 0 2 0 40 0 73 0 115

s 289 290 284 287 187 186 760 763


z 14 13 16 16 43 45 73 74

Central segments tend to “disappear” under (absence of) stress (accent)


Syllable Onset Statistics – CENTRAL Place

Accent


t 241 245 276 230 513 276 1030 751

d 141 143 149 134 173 128 463 405

dx 0 3 0 62 0 179 0 244

n 133 135 237 196 194 130 564 461

nx 0 2 0 40 0 73 0 115

s 289 290 284 287 187 186 760 763


z 14 13 16 16 43 45 73 74

Central segments tend to “disappear” under (absence) of stress (accent)

There is also a tendency for flaps ([dx] and [nx]) to insert under similar conditions


Syllable Onset Statistics – CENTRAL Place

Accent


t 241 245 276 230 513 276 1030 751

d 141 143 149 134 173 128 463 405

dx 0 3 0 62 0 179 0 244

n 133 135 237 196 194 130 564 461

nx 0 2 0 40 0 73 0 115

s 289 290 284 287 187 186 760 763


z 14 13 16 16 43 45 73 74

Syllable Onset Statistics – CENTRAL PlaceCentral segments tend to “disappear” under (absence) of stress (accent)

There is also a tendency for flaps ([dx] and [nx]) to insert under similar conditions

In heavily accented syllables, central segments maintain their canonical identity


Accent


k 185 186 189 187 170 168 544 541

g 115 116 138 137 54 51 307 304

ng 0 0 2 3 1 1 3 4

sh 26 26 40 40 73 80 139 146

zh 0 1 2 9 11 17 13 27

ch 32 34 19 27 22 23 73 84


jh 31 30 52 43 58 48 141 121

w 201 209 310 330 276 287 787 826

q 0 33 0 64 0 38 0 135

Syllable Onset Duration - Posterior PlacePosterior segments are remarkably stable in onset position


Syllable Onset Statistics – Posterior PlacePosterior segments are remarkably stable in onset position

The only significant “deviation” from canonical realization is the intrusion of the glottal stop [q], which lacks phonemic status in English

Accent


k 185 186 189 187 170 168 544 541

g 115 116 138 137 54 51 307 304

ng 0 0 2 3 1 1 3 4

sh 26 26 40 40 73 80 139 146

zh 0 1 2 9 11 17 13 27

ch 32 34 19 27 22 23 73 84


jh 31 30 52 43 58 48 141 121

w 201 209 310 330 276 287 787 826

q 0 33 0 64 0 38 0 135


Accent


r 272 269 233 215 233 162 738 646

l 184 180 226 212 220 162 630 554

hh 158 156 169 157 67 37 394 350

er 0 0 0 2 0 0 0 2

lg 0 2 0 8 0 21 0 31

el 0 1 0 0 0 0 0 1


Syllable Onset Statistics – Place Chameleons“Chameleons” assimilate their place of articulation to the following vowel


Accent


r 272 269 233 215 233 162 738 646

l 184 180 226 212 220 162 630 554

hh 158 156 169 157 67 37 394 350

er 0 0 0 2 0 0 0 2

lg 0 2 0 8 0 21 0 31

el 0 1 0 0 0 0 0 1



They are relatively stable at syllable onset, except in unaccented forms


Accent


r 272 269 233 215 233 162 738 646

l 184 180 226 212 220 162 630 554

hh 158 156 169 157 67 37 394 350

er 0 0 0 2 0 0 0 2

lg 0 2 0 8 0 21 0 31

el 0 1 0 0 0 0 0 1



They are relatively stable at syllable onset, except in unaccented forms

The reduced form of [l] is [lg], a glide-like element – it tends to assume the functional status of [l] in unaccented syllables


PART NINE

Stress Accent’s Impact on Syllable Codas

Stress Accent and Syllable CodasStress accent’s impact on syllable codas differs from that of onsets


The disparity in duration between accented and unaccented forms tends to be significantly less for codas than for onsets (at least when deletions are omitted from consideration)



There is a far greater probability of segmental deletion in coda constituents




Accent level exerts a powerful influence on segmental deletion and on segmental duration




Accent level exerts a powerful influence on segmental deletion and on segmental duration

To a certain degree segmental deletion and duration interact (or are flip sides of the same phonetic coin)

Coda Duration - Accent Level/Syllable FormCoda duration (on average) is similar across syllable structure, both for

accented and unaccented forms


Coda Duration - Accent Level/Syllable FormCoda duration (on average) is similar across syllable structure, both for

accented and unaccented forms

There is a relatively small dynamic range in duration between accented and unaccented codas (relative to onsets and nuclei)


Coda Duration - Accent Level/Syllable FormCoda duration (on average) is similar across syllable structure, both for accented and unaccented forms

There is a relatively small dynamic range in duration between accented and unaccented codas (relative to onsets and nuclei)

Moreover, the duration of certain coda constituents is virtually identical in accented and unaccented syllables


Accent


p 33 32 39 32 17 13 89 77

b 9 6 4 4 1 1 14 11

m 108 96 148 148 112 83 368 327

f 37 36 40 40 36 48 113 124

v 63 55 102 87 172 94 337 236

th 11 10 24 16 34 20 69 46


dh 0 0 0 4 0 5 0 9

Syllable Coda Statistics – Anterior PlaceAnterior coda segments are relatively stable under stress (accent)


Accent


p 33 32 39 32 17 13 89 77

b 9 6 4 4 1 1 14 11

m 108 96 148 148 112 83 368 327

f 37 36 40 40 36 48 113 124

v 63 55 102 87 172 94 337 236

th 11 10 24 16 34 20 69 46


dh 0 0 0 4 0 5 0 9


The segments [m] and [v] are exceptions


Accent


p 33 32 39 32 17 13 89 77

b 9 6 4 4 1 1 14 11

m 108 96 148 148 112 83 368 327

f 37 36 40 40 36 48 113 124

v 63 55 102 87 172 94 337 236

th 11 10 24 16 34 20 69 46


dh 0 0 0 4 0 5 0 9


The segments [m] and [v] are exceptions – they often function as “flaps” in this context, and


Accent


p 33 32 39 32 17 13 89 77

b 9 6 4 4 1 1 14 11

m 108 96 148 148 112 83 368 327

f 37 36 40 40 36 48 113 124

v 63 55 102 87 172 94 337 236

th 11 10 24 16 34 20 69 46


dh 0 0 0 4 0 5 0 9


The segments [m] and [v] are exceptions – they often function as “flaps” in this context, and

They tend to delete in unaccented syllables


Accent


t 322 126 575 191 562 172 1459 489

d 200 119 295 127 370 96 865 342

n 311 237 498 381 773 542 1582 1160

s 142 135 202 214 151 155 495 504

z 179 149 258 208 271 221 708 578


Syllable Coda Statistics – Central PlaceCentral coda segments are extremely unstable under stress (accent)


Accent


t 322 126 575 191 562 172 1459 489

d 200 119 295 127 370 96 865 342

n 311 237 498 381 773 542 1582 1160

s 142 135 202 214 151 155 495 504

z 179 149 258 208 271 221 708 578



(except for the fricatives [s] and [z])


Accent


t 322 126 575 191 562 172 1459 489

d 200 119 295 127 370 96 865 342

n 311 237 498 381 773 542 1582 1160

s 142 135 202 214 151 155 495 504

z 179 149 258 208 271 221 708 578




The segments [t], [d] and [n] tend to delete in coda position, even in heavily accented syllables


Accent


t 322 126 575 191 562 172 1459 489

d 200 119 295 127 370 96 865 342

n 311 237 498 381 773 542 1582 1160

s 142 135 202 214 151 155 495 504

z 179 149 258 208 271 221 708 578




The segments [t], [d] and [n] tend to delete in coda position, even in heavily accented syllables

The major effect of stress accent is its affect on the probability of segmental deletion (which is appreciably higher in unaccented forms)


Syllable Coda Duration - CENTRAL Place

CANONICAL Syllable Forms

The centrally articulated codas exhibit a high probability of deletion, particularly in unaccented syllables – this affects durational properties




The duration of many of the coda segments do not exhibit a difference in duration





Many of the unaccented central codas are short in duration, in contrast to:





Many of the unaccented central codas are short in duration, in contrast to:(1) central onsets





Many of the unaccented central codas are short in duration, in contrast to:(1) central onsets, (2) anterior codas





Many of the unaccented central codas are short in duration, in contrast to:(1) central onsets, (2) anterior codas, (3) posterior codas





Many of the unaccented central codas are short in duration, in contrast to:(1) central onsets, (2) anterior codas, (3) posterior codas, (4) chameleon codas


ALLSyllable Forms

Because of the high probability of deletions for central coda consonants the mean durations are quite low relative to other conditions


ALLSyllable Forms

Because of the high probability of deletions for central coda consonants the mean durations are quite low relative to other conditions

In some sense the default duration for central codas is very short

Accent


k 170 150 196 162 51 39 417 351

g 10 10 8 10 4 5 22 25

q 0 42 0 71 0 54 0 167

ng 63 60 139 126 203 129 405 315

sh 9 9 2 2 4 6 15 17

zh 1 0 0 4 0 2 1 6


ch 26 25 27 25 12 12 65 62

jh 10 10 11 10 15 12 36 32

w 0 4 0 2 0 6 0 12

Syllable Coda Statistics – Posterior PlacePosterior coda segments are relatively stable under stress (accent)


Accent


k 170 150 196 162 51 39 417 351

g 10 10 8 10 4 5 22 25

q 0 42 0 71 0 54 0 167

ng 63 60 139 126 203 129 405 315

sh 9 9 2 2 4 6 15 17

zh 1 0 0 4 0 2 1 6


ch 26 25 27 25 12 12 65 62

jh 10 10 11 10 15 12 36 32

w 0 4 0 2 0 6 0 12

Syllable Coda Statistics – Posterior PlacePosterior coda segments are relatively stable under stress (accent)

The primary exception is [ng], which tends to delete in unaccented syllables


Accent


k 170 150 196 162 51 39 417 351

g 10 10 8 10 4 5 22 25

q 0 42 0 71 0 54 0 167

ng 63 60 139 126 203 129 405 315

sh 9 9 2 2 4 6 15 17

zh 1 0 0 4 0 2 1 6


ch 26 25 27 25 12 12 65 62

jh 10 10 11 10 15 12 36 32

w 0 4 0 2 0 6 0 12

Syllable Coda Statistics – POSTERIOR PlacePosterior coda segments are relatively stable under stress (accent)

The primary exception is [ng], which tends to delete in unaccented syllables

The “infamous” glottal stop [q] tends to insert in this context


Syllable Coda Statistics – Place ChameleonsChameleon segments are unstable under stress (accent)



This is particularly true for [l] (for all levels of accent), where many canonical segments transmute into [lg], particularly in accented forms



This is particularly true for [l] (for all levels of accent), where many canonical segments transmute into [lg], particularly in accented forms

The segment [r] tends to delete in unaccented syllables, but not otherwise


PART TEN

What’s Going on in Pronunciation?

With respect to onset and coda segments, there are two basic forms …

What’s Going On? (in pronunciation)

With respect to onset and coda segments, there are two basic forms …(1) those that are relatively stable across accent level, and


With respect to onset and coda segments, there are two basic forms …(1) those that are relatively stable across accent level, and (2) those that are not


With respect to onset and coda segments, there are two basic forms …(1) those that are relatively stable across accent level, and (2) those that are not

Most of the non-continuants (i.e., stops and nasals) are stable when the locus of articulation constriction is either anterior or posterior


With respect to onset and coda segments, there are two basic forms … (1) those that are relatively stable across accent level, and (2) those that are not


The centrally articulated stops and nasals are highly unstable, particularly in coda position and in unaccented syllables





The place chameleons (i.e., the approximants) are not very stable in either onset or coda position






The vowels form two basic groups –






The vowels form two basic groups – (1) accented






The vowels form two basic groups – (1) accented and (2) unaccented







The accented vowels are generally canonically realized and quasi-evenly distributed across the vowel space








The unaccented forms tend to concentrate in the high-front and high-central regions of the vowel space









Certain segments are actually junctures – e.g., the flaps and the glottal stop










Several other so-called segments are junctures as well










Several other so-called segments are junctures as well (as they function like flaps), the most noteworthy examples are [dh] and [v]










Several other so-called segments are junctures as well (as they function like flaps), the most noteworthy examples are [dh] and [v]

None of these properties is consistent with a segmental model of language


Synopsis

The Rationale for a Juncture-Accent Modelof Spoken Language

Take Home MessagesBased on a detailed analysis of a manually annotated corpus of spontaneous

American English (Switchboard) the following conclusions are drawn:

Based on a detailed analysis of a manually annotated corpus of spontaneous American English (Switchboard) the following conclusions are drawn:

The pattern of pronunciation variation observed is inconsistent with a segmental model of spoken language

Take Home Messages



The pronunciation patterns observed cut across segment and articulatory-feature classes

Take Home Messages




The patterns observed display systematic variation when syllable structure and stress accent are taken into account

Take Home Messages





Therefore, future-generation speech recognition systems need to build syllable structure and stress-accent information into pronunciation models and lexical representations

Take Home Messages





Therefore, future-generation speech recognition systems need to build syllable structure and stress-accent information into pronunciation models and lexical representations

A preliminary juncture-accent model provides a potential starting point for developing more realistic (and robust) lexical representations

Take Home Messages

That’s All, Folks

Many Thanks for Your Time and Attention

Beyond the Phoneme A Juncture-Accent Model of Spoken Language Steven Greenberg, Hannah Carvey, Leah...

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