Third International Conference on Spoken Language Processing (ICSLP 94)

Yokohama, Japan
September 18-22, 1994

Jaw Motions in Speech are Controlled in (at least) Three Degrees of Freedom

David J. Ostry, Eric Vatikiotis-Bateson

ATR Human Information Processing Research Laboratories, Kyoto, Japan; McGill University, Montreal, Canada

In vocal tract models, jaw motions are almost always characterized in terms of sagittal plane rotations about a fixed axis. However, in fact, jaw motion in speech consists of rotation in the midsagittal plane and horizontal and vertical translation. Small amplitude lateral rotations (yaw) are also observed. In this paper, we assess these jaw motion components in speech by examining their patterns of kinematic variation and we contrast these behaviours with the patterns observed in chewing. We also assess the relationship between sagittal plane jaw motions and lateral motions of the jaw. When jaw movements in speech were plotted to show sagittal plane rotation as a function of horizontal translation we observed straight line paths in which the component rotations and translations could vary independently. The vertical elevation of the jaw could also vary, independent of the actual motion path of the jaw. The occurrence of lateral jaw motions in mastication suggests this degree of freedom may be controlled as well.

Full Paper

Bibliographic reference.  Ostry, David J. / Vatikiotis-Bateson, Eric (1994): "Jaw motions in speech are controlled in (at least) three degrees of freedom", In ICSLP-1994, 41-44.