Classification of regional dialects, international dialects, and nonnative accents

Talkers׳ regions of origin and native languages will significantly shape their speech production patterns. Previous results suggest that listeners are highly sensitive to whether a talker is a native or nonnative speaker of the language. Listeners also have some ability to categorize or classify talkers by regional dialect or nonnative accent. However, most previous studies have included variability in only one of these categories (many nonnative accents or many regional dialects). The present study simultaneously examined listeners' perceptual organization of regional dialects and nonnative accents. Talkers representing six United States regional dialects, six international native dialects, and twelve nonnative accents were included in two tasks: an auditory free classification task-in which listeners grouped talkers based on perceived region of origin-and ladder task-in which listeners arranged talkers based on their perceived distance from standard American English. Listeners were sensitive to the distinction between native and nonnative accents, even when presented with a very wide range of dialects and accents. Further, subgroups within the native and nonnative clusters in the free classification task suggested several organizing factors, including perceived distance from the local standard, specific acoustic-phonetic talker characteristics, and speaking rate.