Speech adaptation to dental prostheses: the former lisper.

Six of 13 former lispers studied reported unusual difficulty in speech adaptation to a dental prosthesis. Palatographic data showed that former lispers tended to make more frequent use of A-P shifts in tongue-palate placement as a compensatory strategy than did normal subjects. Tongue advancement was a common pattern. The nonadaptors showed the highest incidence of A-P tongue contact shifts as a compensatory strategy. Their use of this strategy was the most consistent, and they were more likely to retain the same articulatory speech patterns that were tried initially. Tongue groove width data for sibilants of nonadaptors in the familiar conditions showed a substantial incidence of further groove narrowing, a pattern normally seen only when a prosthesis is unfamiliar to the subject. In data on jaw position, nonadapting subjects had either not changed jaw position or adopted a closer jaw position by the end of 2 weeks. In both palatographic and jaw position data, it was possible to distinguish the adapting and nonadapting groups.