his 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. Experiment 1(categorical In test), Thai bilinguals were able to discriminate stop contrasts differing in place of articulation in their two languages, but English-speaking listeners was good only for English. In Experiment 2 (entification test), English stops produced by Thai Speakers were perceived most accurately by both English and Thai listener. English listeners' performance deteriorated when they heard stops in unfamiliar languages. There appeared to be a positive eross-language transfer effect when Thai listeners heard Korean stimuli. Thai bilinguals were a homogenous group with respect to their patterns of stop perception. This suggests robustness of the L1 perception system in adult bilinguals.