Synthetic speech comprehension: a comparison of children with normal and impaired language skills

This study compared the ability of children with normal language (NL) and children with specific language impairment (SLI) to comprehend natural speech and DECtalk synthetic speech by using a sentence verification task. The effect of listening practice on subjects' ability to comprehend both types of speech also was investigated. Subjects were matched for age and sex. Mean nonverbal intelligence scores of the groups did not differ significantly. Results showed that DECtalk was significantly more difficult for all subjects to comprehend than was natural speech and false sentences were significantly more difficult to comprehend than were true sentences. Response latencies shortened significantly from time 1 to time 2 for all subjects. Subjects with SLI had significantly more difficulty comprehending both natural and synthetic speech than did subjects with NL. Implications these results might have for theories of the underlying cause of specific language impairment are discussed.