Articulator movement associated with the development of prosodic control in children.

This study explored the relationship between articulator movement and prosody in children at different developmental ages. Jaw, lower lip, and upper lip kinematics were examined in 4-, 7-, and 11-year-old children as they produced the declarative and interrogative forms of utterances "Show Bob a bot" and "Show Pop a pot." Articulator movement differences were found between declaratives and interrogatives during the production of vowel and consonant targets. The 7- and 11-year-olds differentiated the duration and displacement of their articulator movements to distinguish between declaratives and interrogatives. Several age-related differences in movement duration between the 4-year-olds and the older participants were associated with the production of these targets. Productions of declaratives and interrogatives were not associated with any significant differences in articulator movement variability, although variability did decrease significantly with maturation. The results suggest that children modify their articulator movements to meet the prosodic and linguistic demands of the task. While 4-year-olds appear to be able to modify lip and jaw movement to mark the declarative-interrogative contrast, refinement of these movements continues throughout childhood.