Nature of compensatory speech patterns: Mechanisms responsible for vowel changes

Attempts to compensate for an alteration in palatal configuration produced by wearing dental prosthesis may cause a change in vowel formants. Three prostheses, each with a different configuration, were worn by subjects over a period of a week for each prosthesis. Formant shifts, when present, cannot be predicted from the type of prothesis being worn. Measurements of jaw and larynx position reveal individually distinctive adjustments to the presence of a prosthesis, which can be related to the acoustical characteristics of vowels spoken while wearing the prosthesis. Lowering of the larynx and either a restriction or exaggeration of jaw movements may be seen in the initial stages of speech compensation.