<![CDATA[L2 speech perception is shaped by variability in both talker characteristics and phonetic context, yet how these sources of variability interact remains insufficiently understood. This study investigated how talker accent and vowel context interact to influence L2 speech perception among Thai learners. Thirty-eight Thai undergraduate learners completed an ABX discrimination task testing five English consonant contrasts (/f–θ/, /ð–d/, /θ–ð/, /f–t/, and /t–θ/) produced by five talkers (Thai, Philippine, Indian, British, and American English) across three vocalic environments (high, low, and back vowels). Accuracy was analysed using a binomial generalised linear mixed-effects model (GLMM). Results revealed a significant three-way interaction among consonant contrast, vowel context, and talker (p < .001). Talker effects were limited in high- and back-vowel contexts but pronounced in the low-vowel context. Similarly, vowel-context effects were non-uniform; for instance, low vowels degraded /ð–d/ discrimination for American, Indian, and Thai talkers, whereas back vowels impaired /t–θ/ discrimination specifically for the Thai talker. Overall, no single talker or vowel context provided a uniform perceptual advantage. These findings demonstrate that L2 phoneme discrimination is dynamically co-conditioned by phonetic context and talker variability, carrying important implications for models of L2 speech perception (PAM-L2, SLM-r, L2LP) and contextualised perception pedagogy.]]>
