Welsh is perhaps the most vigorous of the surviving Celtic languages, and has undoubtedly attracted the most modern linguistic research. It is surprising therefore that, while publications on Welsh syntax and phonology have appeared in recent years, no investigation into the sociolinguistics of the language has been available. The linguistic situation in Wales is a complex one, and Welsh as a minority language has not found the establishment and maintenance of a standard form an easy task. Differences between official and literary forms of the language are then quite marked, and many Welsh speakers have not been greatly exposed to these standardising factors. What we find, therefore, are patterns of marked variation in language use. This book explores these patterns, looking at them from the linguistic viewpoint - variation at different levels of language, and from the sociolinguistic viewpoint - regional and social varieties. Also examined are children's speech, important for the future of the language, and the theoretical problems of integrating varying patterns of language use into grammatical description.