Optimality criteria in inverse problems for tongue-jaw interaction

We consider the system of articulators “jaw – tip of the tongue” in order to investigate instant and integral optimality criteria in the variational approach to the solution of speech inverse problem “from total displacement of articulators to their controls”. The required experimental data i.e., coordinates of the tip of the tongue and lower incisor have been measured by the use of the X-ray microbeam system together with EMGs of masseter, longitudinalis superior and longitudinalis inferior. These data have been registered for sequences of syllable /ta/ with different articulation rates, as well as for an elevation and lowering of the tongue tip in nonspeech mode. We analyze instant and integral criteria of the work, kinetic energy, elastic and inertial forces for the system. In speech mode, total displacements of the tongue tip and the jaw are simulated perfectly by the use of any instant and integral criterion, mentioned above. At the same time, the own displacements of the tongue tip and the jaw are reproduced well by means of integral criteria only. On the contrary, the own displacements in non-speech mode are reproduced satisfactory only by the use of any instant optimality criterion.