ASA 129th Meeting - Washington, DC - 1995 May 30 .. Jun 06

5pSC28. Production of highly similar vowels by language-impaired children.

Dept. of Audiol. and Speech Sci., Purdue Univ., West Lafayette, IN 47907

John M. Heinz

Kennedy--Krieger Inst., Baltimore, MD 21202

It has been shown that language impaired (LI) children have greater difficulty than language normal (LN) children in identifying the synthesized vowels /(cursive beta)/ vs /(oe ligature)/, but not /(open aye)/ vs /i/, when the members of test pairs are of equal duration (240 to 40 ms) [R. E. Stark and J. M. Heinz, 2360 (A) (1992)]. It was concluded that, when deprived of the durational cues present in natural speech, LI children were less well able than LN to rely upon subtle spectral cues. In the present study, children in both groups (11 LI, 9 LN) were asked to imitate the synthesized vowels /(cursive beta)/ and /(oe ligature)/. Their responses were recorded, transcribed, and submitted to spectral analysis. Responses of individual children that were given to either /(cursive beta)/ or /(oe ligature)/ were scored as correct, those that were given to both vowels indiscriminately were not. The scores of the two groups were not significantly different. However, the LI children's responses were transcribed as more variable, and occupied a greater range within F[sub 1]-F[sub 2] plots, than those of the LN children. The results support the hypothesis that LI children have ``fuzzy'' phonological categories. [Work supported by NIH.]