| Abstract: | Pulsed ultrasound was used to study tongue movements in the speech of 11 children, aged 3 yrs 3 mo to 11 yrs 6 mo. The stimuli were CV syllables that were produced at a normal speech rate with alternate vowels stressed. In Ss over 6 yrs of age, the pattern of tongue dorsum movement was identical to that observed in adults. For all Ss, the maximum velocity of tongue dorsum raising and lowering was correlated with the extent of the gesture. The slope of the relationship differed for stressed and unstressed vowels, although the differences were not consistent prior to age 6 yrs. For all Ss, the correlation between displacement and peak velocity was accompanied by a relatively constant interval from the initiation of the movement to the point of maximum velocity. The similarity in the tongue dorsum kinematics of children and adults is consistent with the idea that speech motor development involves a refinement of basic modes of motor operation rather than any significant change in the control of the speech apparatus. The speech data obtained are characteristic of systems that can be described by 2nd-order differential equations. (45 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved) |
