Research into the language socialisation of migrant-background children in new educational contexts has pointed to a complex relationship between language, identity, and social integration. This article helps us to further define this relationship in two main ways. Firstly, through focusing on the specific (and largely neglected) context of the experiences of newly-arrived migrant school children from disadvantaged backgrounds and with little initial command of English, in the East of England, which has in recent years seen a steep rise in the population of children from Eastern Europe in particular. Secondly, through inductive analysis of the pupils' accounts of their experience in the new environment, the article identifies four key themes which shed light on the overlap between language, identity, and social integration in this context: perceptions of exclusion in the new language environment, the social boundaries of language use, L1 exchange as communicative capital, and languages and identity simulation.