Organization of tongue articulation for vowels

Abstract

This paper proposes a few basic concepts of motor organization for tongue articulation in relation to articulatory modeling and its control. Our physiological and morphological studies in pursuit of a realistic model of speech production are summarized as three levels of control organization: peripheral mechanisms, motor command generation, and sensorimotor integration. Peripheral organization of articulators can be modeled as a mass-spring system. Tongue musculature is represented as an orthogonal system consisting of two pairs of antagonistic muscles. The low-level control organization is the motor command generator, which transforms intended articulatory trajectories into tiers of motor command sequences. In our model, the input information to the motor command generator is hypothesized as the articulatory trajectory of a vector sum of tongue muscle forces which is derived from electromyographic (EMG) data. The high-level of control organization is the sensorimotor integration which is thought to perform a mapping between auditory and articulatory representations. Our data have suggested that distributions of vowel targets in the muscle force space and in the auditory space are compatible. This topological compatibility in vowel representations implies a tight auditory-articulatory linkage that permits a direct bi-directional mapping between intended motor vowel articulation and its auditory pattern. © 1996 Academic Press Limited.