Second language (L2) learning involves more than simply understanding the grammar or writing system of a new language; it also requires the acquisition of a new sound system. In particular, vowels are particularly difficult to perceive due to the influence of the learners’ native language vowel inventory (Flege, 1995; Escudero, 2005; Best & Tyler, 2007). The present study investigated the role of acoustic similarity in predicting bilingual Lebanese Arabic-English (LA) listeners’ discrimination of Australian English (AusE) vowels. The findings are in line with the predictions based on acoustic similarity in terms of the Second Language Linguistic Perception model (L2LP; Escudero & Boersma, 2004; Escudero, 2005; 2009a). In particular, LA listeners use duration as a cue to facilitate discrimination of AusE vowel contrasts which produces few difficulties. For the LA listeners, discrimination difficulty is only apparent for vowel contrasts where the vowels do not align perfectly with native LA counterparts. Furthermore, when both vowels in the non-native contrast are acoustically similar to or perceived as the same multiple native categories, resulting in an acoustic or perceptual overlap, also contributes to the difficulties in vowel discrimination. Further research is required to test the reliability of the present findings and to establish whether the identified patterns are also detected in speech production
