Tongue bracing under bite block perturbation

Abstract

Speech sounds have been shown to adapt quickly but imperfectly under bite block perturbation, supporting opposing acoustic vs. articulatory compensation mechanisms [Gay et al. JASA 69: 802. 1981; Flege et al. JASA 83: 212. 1998]. The present study considers whether lingual bracing may provide insight into these apparently conflicting findings. Tongue bracing against the teeth or palate is a pervasive posture maintained during normal speech [Gick et al. JSLHR. 60:494. 2017]; we aim to test whether the tongue adapts its bracing position rather than adapting each speech movement individually, providing a single, postural parametric mechanism for responding to jaw perturbation. Results of an experiment will be presented in which native English-speaking participants read aloud passages normally and under bite block conditions translating the jaw in forward, backward or lateral directions, and to varying degrees of opening. Coronal ultrasound imaging results will be reported, measuring positions of the lateral tongue for indications of stable bracing postures. Implications of these findings will be discussed for models of speech production. [Funding from NSERC.]