Tongue position during speech as a function of palatal anatomy: Controls and glossectomy patients

Abstract

This study examined the effect of palatal anatomy on tongue position during the complex speech movement seen in the motion from /ʃ/ to /l/ in “shell.” The study was interested in whether subjects with flatter/narrower palates would use more tongue anteriority than those with higher/wider palates. Anteriority is the percent of the tongue anterior to the first molar. Low palate speakers may use more anteriority due to less space in the palatal vault. The speech task “a shell” requires complicated deformation between the /ʃ/, which elevates the sides of the tongue, and the /l/, which lowers the sides, elevates the tongue tip, and retracts the root. In the past, palate effects have been shown to explain idiosyncratic subject differences. Palate height explained the use of apical vs laminal /s/. Palate width affected the anteriority of tongue position in cancer patients after glossectomy surgery. Therefore, this study examined 16 controls and 8 glossectomy patients. Initial measurements show more anteriority for patients than controls. In addition, patients with a large overbite (vertical overlap between upper and lower incisor) had more anteriority due to a smaller front cavity.