Delivering facts and findings from a variety of multilingual settings, this textbook systematically covers the diverse dimensions of multilingualism. As well as explaining key concepts, it examines the foremost issues of individual and societal multilingualism. It discusses topics from indigenous and minority languages to World Englishes and translanguaging, and from cross-linguistic influence to multilingual identity and the impact of multilingualism on healthy aging and considers the models and research methods used to underpin these discussions. Each chapter is supported by a comprehensive review of relevant research to reveal fresh perspectives, offer discerning insights and pose challenging possibilities for future exploration. .