Detecting phonetic variation versus phonemic differences

Second-language (L2) speech perception research has largely focused on learning to detect phonetic variation which contributes to phonemic differences. However, phonetic variation may emerge for other reasons, e.g., different speakers. In native language acquisition, speech perception is flexible enough to permit speaker-related phonetic variation while at the same time preserving phonemic identity. In L2 speech learning, it remains unclear how speakerrelated phonetic variation is learned or processed. To test how monolinguals and L2 learners handle speaker-related phonetic variation in detecting phonemic differences, the present study investigated the discrimination of novel words spoken in a familiar and unfamiliar accent. Compared to monolinguals, near-native L2 learners made slightly more errors overall and were quicker to attribute large phonetic differences to phonemic differences rather than speaker-related differences. This highlights the challenging task of learning naturally permissible variation in L2 phonemic categories.