Amy Bik May Tsui is Yu-Shan Fellow and Chair Professor of the English Department at National Taiwan Normal University and Professor Emerita at The University of Hong Kong (HKU). She is also former Pro-Vice-Chancellor and Vice-President at HKU, during which she led the historic reform of undergraduate education across the university. She has published extensively on language policy, classroom discourse, conversational analysis, teacher development and teacher expertise. She obtained her PhD in linguistics at Birmingham University (UK) and was awarded Doctor of Education (honoris causa) by the University of Edinburgh (UK) in 2015 in recognition of her outstanding contribution to teaching and learning in higher education and her research excellence. Ernesto Macaro is Emeritus Professor of Applied Linguistics at the University of Oxford in the Department of Education, of which he is also a former Director. Before becoming a teacher educator and researcher, he was a language teacher in secondary schools in the UK for 16 years. His research has focused on second language learning strategies and on the interaction between teachers and learners in second language classrooms. He now applies these foci to classrooms where academic content is being taught through English. He has published widely on these topics and is now considered a world-expert on English Medium Instruction.