Using a framework based on conversation analysis (Auer, 1984, 1995, 1998), this article presents an analysis of learner code-switching between L1 and L2 in an advanced foreign language (FL) classroom. It was found that students code-switch not only as a fallback method when their knowledge of the L2 fails them, or for other participant-related functions, but also for discourse-related functions that contexualize the interactional meaning of their utterances. These uses strikingly resemble code-switching patterns in non-classroom bilingual settings and show that language learners are able to conceptualize the classroom as a bilingual space. Learners orient to the classroom as a community of practice (Wenger, 1998) through their code-switching patterns as manifestations of a shared understanding about their actions and about themselves as members of that community.