This text aims to give teachers and learners of English a wider perspective on language than that often available in standard reference works. It moves beyond basic levels of grammar awareness to foreground the notion of language as a dynamic and powerful communication tool. The book provides a broad framework for readers to reflect upon and discuss issues and views in applied linguistics, sociolinguistics and language education which are of particular relevance to ELT professional development, but also of general interest. These areas include the concepts of language-in-use and associated systems, language varieties, language change and the interaction between language and power. The book is addressed in the main to teachers, but the commentaries make it a flexible reference resource for both taught courses and self-access learning focused on language.