Although not often discussed, complementary ('mother tongue') classrooms comprise participants who differ substantially in a number of ways. Differences comprise, e.g. participants' orientations to and understandings of the indexicalities of linguistic registers, which may have been brought along from the presupposed country of origin. It has local consequences when students and teacher do not share normative models, and students refuse the teacher as an expert authority. For instance, it may disrupt the classroom order and complicate processes of classroom language socialization. The societal context of the complementary classroom also has a potential influence on the local effect of valorized differences. In this paper we illustrate how pronunciation differences are made salient in a Turkish mother tongue classroom in Denmark, and how pronunciation feeds into negotiations of expertise, authority and the keying of classroom activities. Situated humorous performance is juxtaposed and intertwined with practices that conventionally index learning. We compare the case study to the wider societal context to discuss how dominant ideologies of language and education contributed to the teacher's challenges in the specific classroom setting.