At a time when monolingualist claims for the importance of ‘speaking English’ to the national order continue louder than ever, even as language diversity is increasingly part of contemporary British life, literature becomes a space to consider the terms of linguistic belonging. Bad English examines writers including Tom Leonard, James Kelman, Suhayl Saadi, Raman Mundair, Daljit Nagra, Xiaolu Guo, Leila Aboulela, Brian Chikwava, and Caroline Bergvall, who engage multilingually, experimentally, playfully, and ambivalently with English’s power. Considering their invented vernaculars and mixed idioms, their dramatised scenes of languaging – languages learned or lost, acts of translation, scenes of speaking, the exposure and racialised visibility of accent – it argues for a growing field of contemporary literature in Britain pre-eminently concerned with language’s power dynamics, its aesthetic potentialities, and its prosthetic strangeness. Drawing on insights from applied linguistics and translation studies as well as literary scholarship, Bad English explores contemporary arguments about language in Britain – in debates about citizenship or education, in the media or on Twitter, in Home Office policy and asylum legislation – as well as the ways they are taken up in literature. It uncovers both an antagonistic and a productive interplay between language politics and literary form, tracing writers’ articulation of linguistic alienation and ambivalence, as well as the productivity and making-new of radical language practices. Doing so, it refutes the view that language difference and language politics are somehow irrelevant to contemporary Britain and instead argues for their constitutive centrality to the work of novelists and poets whose inside/outside relationship to English in its institutionalised forms is the generative force of their writing.