Dynamic specification of coarticulated vowels

Abstract

An adequate theory of vowel perception must account for perceptual constancy over variations in the acoustic structure of coarticulated vowels contributed by speakers, speaking rate and consonantal context. Recorded consonant-vowel-consonant syllables were modified electronically to investigate the perceptual efficacy of 3 types of acoustic information for vowel identification: static spectral targets, duration of syllabic nuclei and formant transitions into and out of the vowel nucleus. Vowels in /b/-vowel-/b/ syllables spoken by 1 adult male (experiment 1) and 2 females and 2 males (experiment 2) served as the corpus, and 7 modified syllable conditions were generated in which different parts of the digitized waveforms of the syllables were deleted and the temporal relationships of the remaining parts were manipulated. Results of identification tests by untrained listeners indicated that dynamic spectral information, contained in initial and final transitions taken together, was sufficient for accurate identification of vowels even when vowel nuclei were attenuated to silence. The dynamic spectral information appeared to be efficacious even when durational parameters specifying intrinsic vowel length were eliminated.