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C - 226
From Sound to Sense: 50+ Years of Discoveries in Speech Communication
June 11 - June 13, 2004 at MIT
[F18] A new 3D dynamical biomechanical tongue model. Jean-Michel Gérard1, Pascal
Perrier1, Yohan Payan2 & Reiner Wilhelms-Tricarico3, 1Institut de la Communication Parlée &
Université Stendhal, Grenoble, France, 2Laboratoire TIMC, CNRS, Université Joseph Fourier,
Grenoble, France, 3Speech Communication Group, RLE, MIT, Cambridge, MA, USA.
A new dynamical biomechanical tongue model is being developed to study speech motor
control. In spite of its computational complexity, a 3D representation was chosen in order to
account for various contacts between tongue and external structures such as teeth, palate and
vocal tract walls. A fair representation of tongue muscles anatomy is provided, by designing the
Finite Element mesh from the Visible Human® data set (female subject). Model geometry was
then matched to a human speaker, so that simulations can be quantitatively
compared to experimental MRI data. A set of 11 muscles is modeled, which role in speech
gestures is well established. Each muscle is defined by a set of elements which elastic
properties change with muscle activation. Muscles forces are applied to the tongue model via
macrofibers defined within the mesh by muscle specific sets of nodes. These forces are
currently specified as step functions. Boundary conditions are set using zero-displacement
nodes simulating attachments of tongue on bony structures. The non-linear mechanical
properties of tongue soft tissues are modelled using a hyperelastic material. 3D tongue
deformations generated by each muscle, using FEM software ANSYSTM for computation, will
be presented. Implications for speech motor control will be proposed.