Vowels and final consonant production by adults with Down’s syndrome

Abstract

Speech production studies have suggested a typical voice quality as well as vowel and consonant errors in speakers with Down’s syndrome. In this study, the production of bVt or bVd words produced by ten adults with Down’s syndrome and age and gender matched controls was examined for influence of final consonant voicing status. Acoustic measures of vowel duration and consonant voicing were made. Listener judgments were also obtained. Contrasts between vowels pairs were maintained by most subjects, e.g., duration for tense vowels was greater than for lax, although duration for the test subjects productions was greater overall than for the controls. Similarly, consonant voicing contrasts were maintained, e.g., vowel duration preceding voiced consonants was longer than for voiceless, but again overall duration was longer for the Down’s syndrome adults than the controls. The results of the acoustic analyses suggest that while the test subjects demonstrate knowledge for producing final voicing contrasts, aspects of fine coordination are not achieved. Intelligibility of final consonants was high and listener judgments generally agreed with acoustic measures. [Work supported by McNair Scholars’ Program to St. Johns University.]