Informed by Conversation Analysis, this paper examines discursive practices through which nonnative speaker (NNS) identity is constituted in relation to native speaker (NS) identity in naturally occurring English conversations. Drawing on studies of social interaction that view identity as intrinsically a social, dialogic, negotiable entity, I propose that NS/NNS identities are social categories that are made procedurally relevant to the ongoing interaction and that consequently invoke an asymmetrical alignment of the participants. Two sets of videotaped English conversations were analyzed to delineate the sequential organization of the participant framework whereby participants negotiate their NS/NNS identities by aligning and realigning vis-a-vis each other. The analysis shows that participants invoke NS/NNS identities by incidentally undertaking requestor-requestee identities in the midst of a word search and further sustain them by assuming assessor-assessed identities within the situated activity of evaluating self or other's linguistic performance. Invoked NS/NNS identities often undergo renegotiation, which instantly revokes an asymmetry that has arisen between the participants within their NS/NNS identities. The findings indicate that a local asymmetry between an NS and an NNS is not merely an external constraint on participants' discursive conduct but also provides resources for moving the interaction ahead.