Some Acoustic Cues for the Perceptual Categorization of American English Regional Dialects

The perception of phonological differences between regional dialects of American English by naïve listeners has received little attention in the speech perception literature and is still a poorly understood problem. Two experiments were carried out using the TIMIT corpus of spoken sentences produced by talkers from a number of distinct dialect regions in the United States. In Experiment 1, acoustic analysis techniques identified several phonetic features that can be used to distinguish different dialects. In Experiment 2, recordings of the sentences were played back to naïve listeners who were asked to categorize talkers into one of six geographical dialect regions. Results showed that listeners are able to reliably categorize talkers using three broad dialect clusters (New England, South, North/West), but that they have more difficulty categorizing talkers into six smaller regions. Multiple regression analyses on the acoustic measures, the actual dialect affiliation of the talkers, and the categorization responses revealed that the listeners in this study made use of several reliable acoustic-phonetic properties of the dialects in categorizing the talkers. Taken together, the results of these two experiments confirm that naïve listeners have knowledge of phonological differences between dialects and can use this knowledge to categorize talkers by dialect.