This study examined Australian English speakers’ and Thai-English bilingual speakers’ ability to perceive word-final stops in English and Thai. Thai bilinguals lived in Sydney, Australia, for 5.5 years on average (range = 0.2 – 30.3). In Experiment 1
(categorial discrimination test), Thai bilinguals were able to discriminate stop contrasts differing in place of articulation in their two languages with equally high degree of accuracy, but English-speaking listeners’ discrimination was good only for English. In Experiment 2 (identification test), English stops produced by native Thai speakers were perceived most accurately by both English and Thai listeners.
English listeners’ performance deteriorated when they heard stops in unfamiliar languages. There appeared to be a positive cross-language transfer effect when Thai listeners heard Korean stimuli, as word-final stops in both Thai and Korean are phonetically realized as unreleased stops. De- spite a large variation in length of residence in English-speaking countries, Thai bilinguals were a homogeneous group with respect to their patterns of stop perception. This suggests robustness of the L1 perception system in adult bilinguals.