Christopher Hall is Professor of Applied Linguistics in the School of Languages and Linguistics at York St John University. Before joining York St John in 2007, he taught and conducted research for almost 20 years at the University of the Americas in Puebla, Mexico, where he served as Head of the Department of Languages and Research Coordinator for the School of Humanities. His research interests extend from cross-linguistic influence in the multilingual mental lexicon to global Englishes and teacher ontologies of English. He has published numerous articles and book chapters on these topics and is the author or co-author of several books: Morphology and Mind (Routledge, 1992; re-issued 2014); An Introduction to Language and Linguistics. Breaking the Language Spell (Continuum 2005); Mapping Applied Linguistics. A Guide for Students and Practitioners (Routledge, 2011; 2nd edition 2017); Introducing Language in Use (Routledge, 2014; 2nd edition); Ontologies of English (Cambridge University Press, 2020). He supervises research students in the areas of multilingualism, second language acquisition, and global Englishes. He is Reviews Editor for BAAL News, the newsletter of the British Association for Applied Linguistics.