Second International Conference on Spoken Language Processing (ICSLP'92)

Banff, Alberta, Canada
October 13-16, 1992

Mandibular Contributions to Speech Production

Kiyoshi Oshimat (1,2), Vincent L. Gracco (1)

(1) Haskins Laboratories, New Haven, Connecticut, USA
(2) Research Institute of Logopedics and Phoniatrics, University of Tokyo, Tokyo, Japan

In this paper we examine jaw opening and closing action during the production of a variety of vowels and consonants. Of interest was the identification of potential neural control strategies and biomechanical contributions underlying speech production by evaluating, separately and in combination, kinematic and electromyographic (EMG) activity of the jaw at normal and fast speaking rates. We found that EMG and movement characteristics for jaw opening were systematically related and varied according to vowel identity. However, at a fast speaking rate, jaw motion differences were reduced or eliminated for the different vowels, and EMG and movement characteristics for jaw closing were less consistently related and showed fewer consonant-related variations. Inspection of jaw opening and closing movement relations for the different CVCs revealed strong covariation across the movement cycle. In contrast, EMG relations were less related suggesting a substantial biomechanical contribution to jaw closing movement characteristics. Jaw actions were found to be organized around a movement cycle (syllabic unit) suggesting a codependent programming across movement phases (opening/closing). One of the consequences of increased speaking rate was the use of an overall lower than normal peak jaw position for the vowels and consonants and an apparent compensation of the reduced jaw motion by the tongue. Together these results suggests that speech motor control is organized according to vocal tract level goals that span opening and closing actions rather than targets associated with individual articulators.

Full Paper

Bibliographic reference.  Oshimat, Kiyoshi / Gracco, Vincent L. (1992): "Mandibular contributions to speech production", In ICSLP-1992, 775-778.