The influence of utterance length upon bilabial closure duration of selected deaf children.

Measurements were made of intraoral air pressure associated with bilabial closure durations of VCV syllables in sentence-like frames of increasing length for nine deaf and nine matched normal hearing chidren. Results demonstrated significantly longer absolute closure durations at all utterance lengths for the deaf, but with the same relative decrease in closure durations with increases in utterance length for both groups. The deaf children showed lower peak intraoral air pressure values with more variability than the normal children. In addition, the deaf children had longer air-pressure pulse durations than did the normals. Clinical application of these findings to speech management are discussed.