Physiologic Development of Tongue–Jaw Coordination From Childhood to Adulthood

Abstract

Purpose This investigation aimed to examine the development of tongue–jaw coordination during speech from childhood to adolescence. Method Electromagnetic articulography was used to track tongue and jaw motion in 48 children and adults (aged 6–38 years) during productions of /t/ and /k/ embedded in sentences. Results The coordinative organization of the tongue and jaw exhibited changes until the age of 8–11 years and continued to undergo refinement into late adolescence. The tongue–tip and tongue–body were observed to develop unique kinematic relations with the jaw. While tongue–tip movement became increasingly synchronized with jaw movement, tongue–body and jaw retained movement independence but developed a more consistent kinematic relation. Conclusion The present results support the notion that speech motor development is nonuniform, with a refinement period from mid-childhood to late adolescence.