Study of tongue-jaw coordination: Possible role of tongue-hard palate contact in vowel production

Abstract

The inferior-superior displacement of the mandible and tongue were measured photoelectrically (Chuang and Wang, ASA 58.1) during isolated production of [i.e., u, o, and ɑ]. Correlations were calculated between tongue elevation (measured with a mandibular reference) and jaw elevation as an index of their compensatory coordination. Variability of tongue and jaw positioning was obtained as a measure of articulatory precision. The correlations for high and midvowels consistently revealed moderate-to-high negative values, while the low vowels did not show this trend as clearly. The tongue height variation was found to be extremely small for high and midvowels with 0.7-mm deviation on the average, with seven subjects, while the low and back vowels produced variation three to five times greater. With devocalized vowel gestures the correlation and variability values were essentially unchanged. One interpretation of these results was that tongue-hard palate contact provides an external spatial reference for control of high-vowel tongue and jaw positioning, while no such reference is available for low-vowel production. That is, the compensatory control of tongue and jaw movements. or motor equivalence, may be dependent upon receptors in addition to intrinsic muscle receptors for high vowels. This interpretation would be consistent with the lip and jaw coordination reported for consonant articulation. [Work supported by NIH grant NS 13274.]

The Prompt System of Therapy: Theoretical Framework and Applications for Developmental Apraxia of Speech

“…2. In the inferior and superior dimension, the tongue and jaw have shown the same type of reciprocal relationships (Chuang, Abbs, and Netsell, 1978).…”