A continuum mechanics representation of tongue deformation

Understanding the kinematics of the tongue during normal speech will provide important information both for accurate modeling of the acoustics of the vocal tract and for clinical diagnosis and enhanced treatment of persons with abnormal speech due to tongue motion impediments. Measuring tongue motion can be done using magnetic resonance imaging (MRI) which cannot provide the temporal resolution required for normal speech, but can create pseudomovement by imaging a single moment in a vocalization from multiple repetitions of a speech gesture. Finding the relevant biomechanical information from these measurements requires a global kinematic model of tongue motion. Preliminary results from modeling the tongue show that the motion is not that of a rigid body. Indeed, a kinematic model can reveal important biomechanical features, such as regional muscle stretch and velocity requirements as well as the strain distribution. The parameters which describe the kinematic model also provide a quantitative means of comparing the tongue motion, and hence the acoustic control of different subjects.