This paper argues that processes of self-creation are significantly influenced by experiences of schooling, of which language forms a critical aspect. The school is a central site in which identities are contested, negotiated and affirmed, but it is also imbibed with a particular identity that, in the South African context, often remains expressly raced and classed. Existing research has pointed to the salience of language for questions of identity in education, and moreover the relationship between school cultures and the inculcation of particular norms and values. However, in the South African context research should also be focusing on the relationship between the major medium of instruction in schools, English, the values and behaviour encouraged at the school level, and how these influence learners' linguistic and social identities. This paper engages with research conducted in three Cape Town schools and develops the idea of "narratives of social cohesion" to articulate the ways in which different school cultures influence learner-identity formation. It posits that the assumed neutrality of the primary medium of instruction, and its historic association with whiteness, represents a continued undervaluation of black learners' linguistic and social experiences.