Anticipatory co-articulation in the speech of young normal and hearing-impaired French Canadians.

The anticipatory co-articulation in the speech of a group of 10 normal young French Canadians (5 boys, 5 girls) was compared to that found in age-matched groups of 10 moderately hearing-impaired and 10 profoundly hearing-impaired French Canadians. The speech stimuli were the syllables /ti/, /tu/, /ki/, and /ku/, elicited five times each in random order. Acoustic evidence (F2 and centroid frequency measures) of co-articulation was found for all groups; however, the degree of co-articulation was smaller and less consistent across consonants for the two hearing-impaired groups. In particular, the moderately hearing-impaired subjects exhibited a reversal of the expected pattern for [ki] and [ku] stimuli; the profoundly hearing-impaired subjects did not produce sufficient [ki] and [ku] stimuli to measure co-articulatory effects reliably. In general, the profoundly hearing-impaired subjects exhibited the smallest acoustic changes as a result of the vocalic influence on the preceding consonant. Results are considered in relation to theories of speech production deficits in hearing-impaired speakers.