To say that writing has as much claim as speech to be treated as language may strike the reader as a statement of the obvious. But the fact is that, although the tide is beginning to turn now, for most of the twentieth century linguistics has almost wholly ignored writing. It is not necessary to accept all the theories of the French critic Jacques Derrida in order to agree with him when he describes writing as "the wandering outcast of linguistics." This book is offered in the belief that written language is a form of language. As such, it deserves to be treated with the methods of modern, scientific linguistic study, which have been increasing our understanding of the spoken form of language for many decades.