Research on ethnicity and social class in primary school has shown how school produces social inequality and seems to suffer from a lack of professional diversity competence. Less work has examined how a democratic, equality-oriented curriculum puts hierarchies and differences into play. Our study is based on an ethnographic text material in form of a home–school correspondence from two ethnically and socioeconomically different parts of Oslo, Norway. We examine how families (children and mothers, as co-writers) portray their domestic family life. Our aim is to explore how ethnicity and social class become visible through what we call ‘linguistic habitus’, ‘linguistic negotiation’ and ‘domestic capital’ in an apparently conform school programme. Drawing on a Bourdieu-inspired focus on power in language use, we argue that this home–school correspondence functions as a linguistic market: a system of distinction, operating with internal rules regarding what to say, how to say it and what not to say. Building on 319 family entries from a home–school correspondence, this study demonstrates how a corpus of saturated and intertwined texts reveals hegemonic middle-class preferences, values and identities. Mothers from the middle-class areas, co-writing with their children, reap symbolic benefits more easily than mothers and children from socio-economical diverse areas, who lose ground in this linguistic market. Despite the fact that the majority of the entries are similar and conform to a standard, some counter-discourses emerge. The study identifies the development of three linguistic trajectories: counteroffensive, rectifying and ‘hyper-correct’ deviance. A central argument in this article is that this well-meaning home–school correspondence, which aims to be inclusive and democratic, demonstrates that access is socially skewed and that language capital is crucial. Our study reveals that the school system in Norway, situated in a very equality-oriented and strong welfare state, is based on two opposing ideologies, diversity on the one hand and sameness on the other.