The perceptual contribution of consonants and vowels to sentence recognition: Effect of dialect variation in American English

In background noise, the amplitude fluctuations of speech commonly provide for momentary glimpses of high intensity portions of speech, predominantly from vowels. Previous investigations have provided glimpses of consonants or vowels to determine the perceptual contribution of different speech acoustics to sentence intelligibility. The present study investigated the consistency of perceptual contributions across eight American English dialects for a group of listeners from the southern United States. Results demonstrated that sentences preserving predominant vowel acoustics were consistently more intelligible across dialects for all participants. The significant contribution of vowels does not appear dependent on familiarity with properties of dialectal variation but may represent the preservation of more general acoustic cues important for sentence recognition. Acoustic analyses of temporal amplitude modulation suggest important cues present during vowels and highlight gradient differences across dialects associated with intelligibility.