Formant amplitude of children with Down syndrome.

The sustained vowel sounds of 14 noninstitutionalized 7- to 10-year-old children with Down syndrome and 14 nonretarded 7- to 10-year-old children were analyzed acoustically in terms of vowel formant amplitude levels. Taped speech samples were subjected to narrowband realtime analysis, and the levels of both groups were compared statistically. The speakers with Down syndrome had formant amplitude intensity levels that were significantly lower than those of a similar group of nonretarded speakers.