This chapter explores the social dynamics and communicative practices of shared housing through the lens of language socialisation. Drawing on interview data from diverse London households, it examines how residents internalise unspoken norms and develop the interactional competence necessary to navigate life with strangers. The chapter opens by outlining the general communication culture in shared homes, where maintaining peace often takes precedence over meaningful engagement. House sharers learn to manage boundaries, negotiate routines, and limit interactions as strategies to minimise conflict and emotional strain. These practices form what is described here as a “cost of communication”, where social engagement is weighed against its risks. The chapter also considers how intercultural and linguistic differences introduce further complexity, with misunderstandings and even intentional provocations shaping household dynamics. Language emerges not only as a tool for connection, but also for boundary-making, resistance, and the negotiation of power. Ultimately, the chapter argues that becoming a competent house sharer involves acquiring a communicative repertoire, necessary to survive the emotional and social demands of shared living.