Reflecting a multitude of developments in the study of language change and variation over the last ten years, this extensively updated second edition features a number of new chapters and remains the authoritative reference volume on a core research area in linguistics. * A fully revised and expanded edition of this acclaimed reference work, which has established its reputation based on its unrivalled scope and depth of analysis in this interdisciplinary field * Includes seven new chapters, while the remainder have undergone thorough revision and updating to incorporate the latest research and reflect numerous developments in the field * Accessibly structured by theme, covering topics including data collection and evaluation, linguistic structure, language and time, language contact, language domains, and social differentiation * Brings together an experienced, international editorial and contributor team to provides an unrivalled learning, teaching and reference tool for researchers and students in sociolinguistics