This chapter introduces the central concern of the book: the growing housing crisis in global cities like London, which has made house sharing a necessity for many adult working professionals, particularly single millennials. The chapter frames shared housing not just as an economic condition, but as a communicative, social, and identity-laden experience shaped by language. It presents the research questions guiding the study, focusing on how individuals negotiate household relationships, navigate spatial and social boundaries, and experience inequalities and precarity, particularly through the lenses of migration, ethnicity, and linguistic background. Methodologically, the chapter introduces the participants, London-based single professionals living with unrelated housemates, and outlines the discourse analytic framework used to explore their lived experiences. In doing so, it establishes the book’s interdisciplinary contribution to sociolinguistics, urban studies, and housing research by linking everyday language practices to broader questions of inequality and precarity in terms of housing. The chapter concludes by outlining the book’s structure and its focus on household communication in London’s shared houses.