Effects of exposure to dialect-specific allophonic variation on perceptual similarity ratings of vowels

Dialect exposure affects listeners’ lexical processing. In this study, we examined whether listeners’ exposure to dialect-specific allophonic variation in two linguistic variables in American English (nasal split /æ/ system and pre-voiceless /ɑɪ/ raising) affects their perceptual similarity ratings of matching versus mismatching allophones. Listeners from the U.S. North were assumed to have more exposure to pre-voiceless /ɑɪ/ raising and less exposure to a nasal split /æ/ system, while listeners from the U.S. Midland were assumed to have more exposure to a nasal split /æ/ system and less exposure to pre-voiceless /ɑɪ/ raising. We analyzed Northern and Midland listeners’ perceptual similarity ratings on a 1–5 scale for three types of auditory vowel pairs: match (e.g., ban-bang or bike-bite), allophonic mismatch (e.g., ban-bat or bike-bide), and phonemic mismatch (e.g., ban-bike). We predict that listeners with more exposure to dialect-specific allophonic variation should rate allophonic mismatches as more different than allophonic matches compared to listeners with less exposure. Preliminary results suggest that listeners rate allophonic matches as more similar than allophonic mismatches, and both of these types are rated as more similar than phonemic mismatches, consistent with existing literature. There was no effect of dialect exposure to allophonic variation on perceptual similarity ratings.