Gestural Timing and Magnitude of English /r/:

An Ultrasound-OptoTrak Study

Fiona Campbell, Bryan Gick, Ian Wilson, and Eric Vatikiotis-Bateson

Ultrafest IV Tucson, ArizonaApril 14, 2005

Goals To better understand the gestural organization of

composite segments in English. Contribute to the knowledge of mechanisms for

production of English /r/ Improve on past methodology by testing

combined B/M-mode ultrasound and Optotrak as a means to increase temporal resolution while imaging the vocal tract from lips to tongue root.

Introduction Generalizations from previous studies:

Temporal: More anterior gestures appear at syllable peripheries. Nasals, /l/, /w/ (Krakow, 1999; Gick, 2003)

Spatial: Position-dependent spatial reduction of gestures. (Sproat & Fujimura, 1993) Final position reduction of anterior gestures & Initial position reduction of less anterior gestures

Proposed Explanations A number of explanations have been proposed

to account for these generalizations, including:• Sproat & Fujimura (1993)• Browman & Goldstein (1995)• Gick (2003)• Carter (2002)• Gick, Campbell, Oh, and Tamburri-Watt (in press)

All studies thus far have been based on a comparison of two gestures

English /r/ Composed of 3 constrictions:

tongue root at the pharyngeal wall (TR) tongue tip/blade at the palate(TB) between the lips (Lip)

Variable tongue shape, more lip rounding and more prominent TB gesture in Initial position. (Zawadzki & Kuehn, 1980)

Examination of three gestures will help disambiguate the predictions made by different theories.

PredictionsSummary of predicted categorization of gestures

and predictions of relative timing by position: Lip TB TR Initial Final

Sproat & Fujimura (1993)

[vocalic] [vocalic] [vocalic] All three simultaneous,All three reduced

All three simultaneous,No reduction

Browman & Goldstein(1995)

narrower constriction(than TR)

narrower constriction(than TR)

wider constriction

All three simultaneous.

TR > LipTR > TBTB & Lip reduced

Gick (2003) C-gesture C-gesture V-gesture Lip & TB > TR,TR reduced

TR > Lip & TBLip & TB reduced

Carter (2002)

? seemingly consonantal

seemingly vocalic

Any order:dialect dependent

(Lip)/TR > TB/(Lip)

Gick et al (in press)

anterior less anterior least anterior

All three simultaneous

TR > TB > Lip

Methods Optotrak 3D motion and position

measurement (point tracking) system and B/M-mode ultrasound video were used to simultaneously record the three gestures of /r/ in syllable-initial, and syllable-final positions preceding a consonant and preceding a vowel in several vocalic contexts.

Participants

10 people, 5 women, 5 men Native speakers of Canadian English 8 from Western Canada One of the male subjects had to be

excluded from the analysis due to poor ultrasound image quality.

StimuliThe position of /r/ varied within a given vocalic context such

that:Syllable-initial Resyllabifiable Syllable-final...V1# RV1... ...V1R# V1... ...V1R# hV1...

V1 = /e/ (Lips, TR visible)

V1 = /a/ (Lips, TB visible)

Stimuli were randomized and presented in a carrier phrase which was read by the subject.

… said “_________” each… x 10 for each stimuluseg. Cindy said "hay ray" each afternoon.

Data Collection The subject was seated in a modified ophthalmic

examination chair to maximize head stability and Ultrasound probe contact.

Stimuli were presented on a laptop located about 2m away from the subject at eye level.

Timed PowerPoint presentation: 130s trials A 'clapper' with an Optotrak marker attached

was used to set a 0 point for synchronization of the Optotrak, Ultrasound, and Audio signals.

Experimental Set-up

Data Collection II Ultrasound: B/M mode: midsagittal section

(29.97fps) + continuous movement trajectories of A (TT), B (TM), C (TR) recorded to DV.

Optotrak 3020 system: recorded (at 90 Hz) the 3D positions of 12 infrared-emitting diode Optotrak markers.

Audio: signal recorded synchronized with both Optotrak and Ultrasound data signals.

Optotrak Marker Placement

Ultrasound Data

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Ultrasound Measures: Timing

Ultrasound Measures: Magnitude

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Optotrak Measures

Qualitative ObservationsSagittal diagram of idealized tongue shapes for American /r/

(Modified from Hagiwara, 1995, p.97)

Tip Down

Blade UpTip Up

Results: Timing

Results: Magnitude

Qualitative Results All three tongue shapes observed No speaker used more than two of these ‘blade up’ was most common across

subjects and most stable across positions Tongue shape varied by both vowel

context and syllable position Higher TB syllable-initially and in the

context of low or back vowels

Tongue Shape Variability

Summary The position-based differences observed

in the overall results were: Initial

• Timing: front-to-back• Spatial reduction: TR

Final:• Timing: TR & Lip simultaneous; precede TB• Spatial reduction: TB and Lips

Surprises?

Three-way timing distinction in Initial position

Lip patterns with TR in terms of timing but with TB in terms of spatial reduction in Final position

The results are not consistent with any of the proposals considered

Proposal Timing patterns depend on magnitude

Relative width of constrictions determines order (Browman & Goldstein, 1995, but in both positions).

Narrower constriction(s) at syllable edges Relative width can vary as a result of positional

reduction

Possible motivating factor: Constriction width: Jaw height

Potential Problems Potential for error in calculations

Unclear data for Resyllabifiable condition

Stationary M-mode lines, variable tongue shape

No head correction

Conclusions Accounts employing a binary categorical system

are challenged by the observed three-way timing distinction in Initial position.

The results of this study suggest a dependence relationship between the relative timing of gestures and their magnitude.

Future work may be able to test this proposal by measuring the actual relative constriction width of each gesture across positions.

Selected ReferencesBrowman, C. P., & Goldstein, L. (1992). Articulatory phonology: An overview.

Phonetica, 49, 155-180.Carter, P. (2002). Structured variation in british english liquids: The role of

resonance. Unpublished PhD Dissertation, University of York.Delattre, P., & Freeman, D. (1968). A dialect study of american r’s by x-ray motion

picture. Linguistics, 44, 29-68.Gick, B. (1999). A gesture-based account of intrusive consonants in english.

Phonology, 16, 29-54.Gick, B. (2003). Articulatory correlates of ambisyllabicity in english glides and liquids.

In J. Local, R. Ogden & R. Temple (Eds.), Labphon VI: Constraints on phonetic interpretation. Cambridge: Cambridge University Press.

Gick, B., Campbell, F., Oh, S., & Tamburri-Watt, L. (in press). Toward universals in the gestural organization of syllables: A cross-linguistics study of liquids. Journal of Phonetics.

Hagiwara, R. (1995). Acoustic realizations of american /r/ as produced by women and men. UCLA Working Papers in Phonetics, 90, 1-187.

Krakow, R. A. (1999). Physiological organization of syllables: A review. Journal of Phonetics, 27, 23-54.

Sproat, R., & Fujimura, O. (1993). Allophonic variation in english /l/ and its implications for phonetic implementation. Journal of Phonetics, 21, 291-311.

Uldall, E. (1958) ‘American “molar” R and “flapped” T.’ Revista do Laboratorio de Fonetica Experimental, Universidad de Coimbra 4. 103-6.

Zawadzki, P. A., & Kuehn, D. P. (1980). A cineradiographic study of static and dynamic aspects of american english /r/. Phonetica, 37, 253-266.