Intelligibility of Unfamiliar Accents in Quiet and Noise Develops Into Adolescence

PURPOSE: School-aged children have more difficulty understanding talkers with unfamiliar accents than adults, but little is known about when this ability matures. This study examines when word recognition for unfamiliar accents matures in quiet and noise as well as how phonetic distance contributes to word recognition. METHOD: = 200). The sentences were spoken by one familiar first language (L1)-accented, one bilingual-accented, five second language (L2)-accented, and two unfamiliar L1-accented female talkers. The pointwise mutual information-based Levenshtein distance metric quantified phonetic distance of the talkers' productions from local norms. RESULTS: Children's word recognition was poorer than adults for all unfamiliar accents in both noise and quiet. Adolescents' word recognition for the unfamiliar accents was similar to that of adults in quiet for accents that were phonetically closer to the familiar L1 accent but was lower than that of adults for talkers whose phonetic distances were more distant. In noise, all L2 accents resulted in poorer accuracy for adolescents. CONCLUSIONS: Foundational skills for coping with speech variability emerge early in development. However, adeptly using them for spoken word recognition in noise follows a protracted developmental trajectory that requires more than 15 years of development and listening experience. The results have implications for children with sensory aids, as indexical variability can be particularly problematic because of their degraded spectrotemporal resolution.