Effects of speaking rate on vowel identification

To examine the role of context in providing temporal information that supports identification of vowels, eleven t-vowel-t syllables were excised from a carrier sentence spoken at both normal and rapid speaking rates by an adult male talker. Separate groups of subjects identified vowels in the syllables presented in the following contexts: (1) in isolation, (2) embedded in the inappropriate rate carrier sentence, (3) embedded in the appropriate rate carrier sentence, and (4) accompanied by the immediately preceding word (“the”) from the rapidly-produced carrier (minimal context). Vowel identification was highly accurate for normal rate targets in all contexts. For rapidly produced syllables were most frequent for syllables in isolation, intermediate for syllables in inappropriate rate and minimal contexts, and least frequent for syllables in appropriate rate context. Most errors in the identification of rapid targets occurred on “intrinsically long” intended vowels. The results indicate that vowels may be incompletely specified in a single syllable of rapid speech, and that the surrounding speech context may provide temporal information necessary for accurate vowel identification. [Work supported by NIMH, NICHHD, NSF.]