Speech Production

INTRODUCTION Understanding speech production requires a synthesis of perspectives found in physiology, motor control, cognitive science, and linguistics. Here we focus on presenting work in the areas of motor control, dynamical systems and neural networks, and linguistics which we feel is critical in understanding functional architecture and characteristics of the speech production system. Centuries of research in linguistics have provided considerable evidence that there are fundamental cognitive units that structure language. Spoken word forms are not unstructured wholes but rather are composed from a limited inventory of phonological units which have no independent meaning but can be (relatively freely) combined and organized in the construction of word forms. While languages differ in their selection of phonological units, within a given language there is a relatively small fixed set. Unlike certain other domains of human movement in which the existence of component action units remains controversial (see MOTOR PRIMITIVES; ARM AND HAND MOVEMENT), the production of speech by the lips, tongue, vocal folds, velum (the port to the nasal passages), and respiratory system can be understood as arising from choreographed linguistic action units. A variety of micro to macro level units has been suggested as Some of the above hypothesized units are mutually exclusive by definition (e.g. features & gestures); others have been assumed to co-exist and/or be hierarchically structured (e.