Lubker J F
Clin Plast Surg. 1975 Apr;2(2):249-59.
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.
前文所呈现的是正常言语产生过程中腭咽功能理论的大致轮廓。有人提出，腭咽肌肉组织以可预测的可变方式发挥作用，以提供可预测的可变结构运动和定位。基于协同发音现象，鉴于已知结构所在位置、为产生可感知的可接受音素它们必须到达的位置以及随后为后续音素它们必须处于的位置，这种变异性是可预测的。如下文将讨论的，该理论并不完整。然而，它展示了腭咽功能的复杂性。该机制的运动同时涉及许多变量，仅考虑一块肌肉、一个结构或一个音素是不够的。系统中任何一块肌肉的作用都会受到其他肌肉作用的影响，任何一个结构的运动都会受到其他结构运动的影响，并且任何一个音素都会受到其周围音素的影响——有时影响很大。因此，口腔化和鼻音化手势的中枢神经系统编程必定是一个复杂的过程。当然，该编程的结果是复杂的。
