Normal velopharyngeal function in speech.

What has been presented in the foregoing pages is the broad outline of a theory of velopharyngeal function in normal speech production. It is suggested that the velopharyngeal musculature functions in a predictably variable manner to provide predictably variable structural movements and positioning. The variability is predictable, based on the phenomenon of coarticulation, given knowledge of where the structures are, where they must go to produce a perceptually acceptable phonime, and where they must subsequently be for later phonemes. The theory is not complete, as will be discussed below. Nevertheless, it demonstrates the complexity of velopharyngeal function. Many variables are involved simultaneously in the movements of this mechanism, and it is not enough to consider a muscle, a structure, or a phoneme. The action of any muscle is influenced by the action of others in the system, the movements of any structure are influenced by movements of other structures, and any phoneme is influenced-sometimes heavily so-by phonemes around it. Thus, the central nervous system programming of oralization and nasalization gestures must be a complicated process. Certainly, the results of that programming are complicated.