At a time when globalization and the advent of the internet have accelerated the spread and diversification of English varieties worldwide, this book provides a constructive assessment of the theoretical models that best account for the development and use of Englishes in the early 21st century. In this endeavor, the present book brings together contributions by scholars who explore the notion of linguistic globalization based on a wide range of ESLs, EFLs and ELF, synchronic and diachronic data, different methodological approaches (corpus-based, sociolinguistic, ethnographic), and a variety of data resources (social media, multiplayer online games, journalistic data, GloWbE, Corpus of Historical Singapore English, thematic blogs). Collectively, these studies serve as a springboard for future research on the globalization of Englishes and they contribute to a timely and necessary scholarly conversation on what constitutes adequate theoretical models of World Englishes in the 21st century.