The aim of this book is to introduce readers to a variety of approaches to lexical, morpho-syntactic and discourse-pragmatic variation in English and some of the research methods used in the various disciplines. The book presupposes a sound knowledge of linguistics but no specific knowledge of discourse analysis, pragmatics, sociolinguistics, etc. per se. The subject has been of vital importance to the teaching of English as a Second Language and throughout the book emphasis will be made on the relevance of variation analysis to teaching and learning English. The ultimate goal is to develop an awareness of how to select teaching materials that are authentic and natural and to distinguish them from what is artificial or goes counter to the way naturally-occurring language is used and structured.