Perception of synthesized vowel pairs by normal and specifically language impaired (SLI) children.

Abstract

It has been proposed that SLI children have a rapid-rate auditory-processing deficit, and alternatively, that they have special difficulty with signals that are low in information or degraded. In the present study, steady-state vowel pairs, /a/–/i/ and /æ/–/eh/, were presented to 20 normal and 20 SLI children within a series of tasks, namely, discrimination, in which they had to detect change/no-change in a series; identification where they identified stimuli presented one at a time; and sequencing, where they indicated order of presentation of paired stimuli. For both vowel pairs, short (40–5 ms) and long (240–40 ms) series were presented. It was found that the performance of the SLI children was not significantly different from the normals’ in tasks involving /a/–/i/. Both groups of children had greater difficulty with the /æ/–/eh/ than the /a/–/i/ tasks, but the SLI children showed significantly greater decrement in performance than normals for /æ/ vs /eh/. Neither group showed a significant effect of vowel duration. Implications of these findings for child language impairment will be discussed. [Work supported by NIH.]