Date of Degree

2002

Document Type

Dissertation

Degree Name

Ph.D.

Program

Speech-Language-Hearing Sciences

Advisor

Richard G. Schwartz

Committee Members

Lawrence Raphael

Valerie Shafer

Judith Gravel

Subject Categories

Speech and Hearing Science

Abstract

The perception of temporal speech cues, lexical knowledge, and their interactions were examined in children (6;0-9;6) with specific language impairment (SLI). An identification task was used to test four 12-step speech continua: word-word (FEET—FEED), nonword-nonword (ZEST—ZEED), word-nonword (CHEAT—CHEED) and nonword-word (REAT—READ). The stimuli were naturally recorded and digitally edited. The vowel steady state, which varied in duration from 110 to 350 milliseconds in 20-millisecond steps, was the acoustic cue to the voicing characteristic of the final consonant in each stimulus. The analyses revealed that both the TLD and SLI groups used vowel duration as a perceptual cue. For the word-word condition, SLI and TLD did not differ in their responses. There were group differences for the three remaining continua. For the nonword-nonword condition, the word-nonword and the nonword-word conditions, SLI demonstrated less response certainty than their TLD peers. In addition, children with SLI had different category boundaries than the TLD group. Both groups demonstrated a word bias effect, however, it was stronger for the SLI group. Therefore, children with SLI use vowel duration as a cue to the final consonant voicing characteristic, however the use of this cue is weak: their perceptual judgments are influenced more readily by higher-level lexical knowledge than children who are TLD.

Comments

Digital reproduction from the UMI microform.

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