This book is the first comprehensive, research-based description of the development, structure, and use of Welsh English, a contact-induced variety of English spoken in the British Isles. Present-day accents and dialects of Welsh English are the combined outcome of historical language shift from Welsh to English, continued bilingualism, intense contacts between Wales and England, and multicultural immigration. As a result, Welsh English is a distinctive, regionally and sociolinguistically diverse variety, whose status is not easily categorized. In addition to existing research, the present volume utilizes a wide range of spoken corpus data gathered from across Wales in order to describe the phonology, lexis, and grammar of the variety. It includes discussion of sociolinguistic and cultural contexts, and of ongoing change in Welsh English. The place that Welsh English occupies in relation to other Englishes in the Inner and Outer Circles is also analysed. The book is accessible to the non-specialist, but of particular use to scholars, teachers, and students interested in English in Wales, Britain, and the world. It provides an unparelleled resource on this long-standing and vibrant variety.