Supplementary Material for: Comparative Acoustic Analyses of L2 English: The Search for Systematic Variation

Background/Aims: Previous research has shown that exposure to multiple foreign accents facilitates adaptation to an untrained novel accent. One explanation is that L2 speech varies systematically such that there are commonalities in the productions of nonnative speakers, regardless of their language background. Methods: A systematic acoustic comparison was conducted between 3 native English speakers and 6 nonnative accents. Voice onset time, unstressed vowel duration, and formant values of stressed and unstressed vowels were analyzed, comparing each nonnative accent to the native English talkers. A subsequent perception experiment tests what effect training on regionally accented voices has on the participant’s comprehension of nonnative accented speech to investigate the importance of within-speaker variation on attunement and generalization. Results: Data for each measure show substantial variability across speakers, reflecting phonetic transfer from individual L1s, as well as substantial inconsistency and variability in pronunciation, rather than commonalities in their productions. Training on native English varieties did not improve participants’ accuracy in understanding nonnative speech. Conclusion: These findings are more consistent with a hypothesis of accent attune­ment wherein listeners track general patterns of nonnative speech rather than relying on overlapping acoustic signals between speakers.