Extending perceptual assimilation model to L3 phonological acquisition

The scarcity of research on speech perception among multilingual speakers precludes a full understanding of phonological acquisition in the third language (L3). In this controlled case study, we investigate L3 phonological acquisition in the perceptual domain and test the predictions of Perceptual Assimilation Model- L2 (Best & Tyler, 2007) adopted for multilingual learners. We employed an AX discrimination task, testing categorical discrimination of Polish sibilants, and a cross-linguistic similarity task, testing perceptual distance between Polish, English and German vowels. We examined L3 Polish perception in 10 multilinguals (aged 14) with L1 German and L2 English who differed in terms of language status (heritage vs. non-heritage). Their perception tasks performance was analysed for accuracy and reaction time. The cross-linguistic similarity task demonstrated that multilinguals assimilate some L3 sounds to both L1 and L2 categories, with a preference for the latter. In the majority of cases multilinguals make a distinction between similar L1, L2 and L3 sounds. The AX results showed that even beginner L3 learners distinguish highly similar L3 sibilant pairs. Our data suggests that the PAM-L2 model could also be extended to L3 acquisition; however, beginner L3 learners seem more likely to perceive subtle acoustic differences in novel phonological contrast