Homonymy and the voiced-voiceless distinction in the speech of children with specific language impairment.

Two studies are reported in which homonymy in the speech of children with specific language impairment (SLI) was examined. In the first study, the degree of homonymy reflected in the speech of 14 SLI children was found to resemble that seen in the speech of a group of language-matched children with normal language (NL). Within each group there was considerable variation in the degree of homonymy observed. An examination of the sound changes that contributed to the children's use of homonymy suggested that homonyms arising from prevocalic voicing were more frequent in the speech of the NL children. The second study represented a more systematic examination of prevocalic voicing differences between NL and SLI children. Minimal pairs differing only in the voicing feature of the initial consonant were produced by four SLI and four language-matched NL children. The SLI children showed greater ability to distinguish the minimal pairs by means of a voiced-voiceless initial consonant contrast, as measured by voice onset time as well as by phonetic transcription. The linguistic and neuromotor factors contributing to the findings are discussed.