Accent Intelligibility Differences in Noise Across Native and Nonnative Accents: Effects of Talker-Listener Pairing at Acoustic-Phonetic and Lexical Levels

PURPOSE: The intelligibility of an accent strongly depends on the specific talker–listener pairing. To explore the causes of this phenomenon, we investigated the relationship between acoustic–phonetic similarity and accent intelligibility across native (1st language) and nonnative (2nd language) talker–listener pairings. We also used online measures to observe processing differences in quiet. METHOD: English (n = 16) and Spanish (n = 16) listeners heard Standard Southern British English, Glaswegian English, and Spanish-accented English in a speech recognition task (in quiet and noise) and an electroencephalogram task (quiet only) designed to assess phonological and lexical processing. Stimuli were drawn from the nonnative speech recognition sentences (Stringer & Iverson, 2019). The acoustic–phonetic similarity between listeners' accents and the 3 accents was calculated using the ACCDIST metric (Huckvale, 2004, 2007). RESULTS: Talker–listener pairing had a clear influence on accent intelligibility. This was linked to the phonetic similarity of the talkers and the listeners, but similarity could not account for all findings. The influence of talker–listener pairing on lexical processing was less clear; the N400 effect was mostly robust to accent mismatches, with some relationship to intelligibility. CONCLUSION: These findings suggest that the influence of talker–listener pairing on intelligibility may be partly attributable to accent similarity in addition to accent familiarity. Online measures also show that differences in talker–listener accents can disrupt processing in quiet even where accents are highly intelligible