Syntactic, semantic, and rhythmic influences on children's and adults' motor programming of speech.

The influence of linguistic and paralinguistic structure on speech motor programming was investigated for 5-year-olds, 8-year-olds, and adults. Subjects repeated verbal stimuli, each at maximum rate on numerous consecutive trials. It was hypothesized that structure in an utterance would allow a speaker to organize its motor program more efficiently than would be possible for an otherwise identical utterance that lacked such structure, although the types of structure employed might change with age. Differences in the efficiency of motor program organization were expected to be evidenced in the syllable duration and the relative variability of the syllable duration of subjects' repetitions. At all ages, repetition durations were shorter for stimuli with a sentencelike rhythm than for unstructured stimuli. Stimuli that were syntactically structured and contained a sentencelike rhythm were spoken with shorter durations than nonsyntactic stimuli with sentential rhythm but only by 8-year-olds and adults.