This article presents a linguistic ethnographic study of a Panjabi complementary school in Birmingham, UK. Researchers observed classes for one academic year, writing field notes, conducting interviews, and making digital audio recordings of linguistic interactions. Sets of beliefs about the production and deployment of certain linguistic signs were powerfully in play in the language learning classroom, as teachers and students negotiated what counts as the authenticity and legitimacy of the "native speaker" teacher. Analysis of examples from empirical linguistic material focuses on the ways in which local practices constitute, and are related to, orders of indexicality and language ideologies. Analytical discussion offers an understanding of complex, situated, and nuanced negotiations of power in claiming and assigning authenticity and legitimacy in language learning contexts. The article considers the construction of the "native speaker" heritage language teacher, and asks what counts as authentic and legitimate in teaching the community language, Panjabi, to a group of English-born young people who share Panjabi as a cultural and linguistic heritage.