Abstract:
Oral morphology varies significantly between individuals and must be taken into account during speech development. The present study examines adaptations to a modification of the shape of the alveolar region of the palate. Adult subjects were fitted with artificial palate prostheses and acoustic and kinematic variables were measured during the production of /s/. Recordings were made preceding and immediately following the insertion of the palate. The key feature of the study is that the post-insertion training is controlled. Initially, subjects practice only static /s/. Following this, different target words are practiced in sequence. OPTOTRAK was used to make kinematic measures of the movements of the lips and jaw. Analyses of the centroid, skewness, and kurtosis of the spectral distributions of the /s/ acoustics were carried out. Preliminary results indicate that there are significant changes in the spectra of the fricatives following insertion of the artificial palate and that adaptations require extended training. Further, compensations appear to vary with phonetic environment. Results will be discussed in relation to models of coarticulation.