David Singleton is Fellow Emeritus, Trinity College Dublin, Ireland, Professor Emeritus, University of Pannonia, Hungary and Professor, University of Applied Sciences, Konin, Poland. He is the author of numerous monographs and textbooks, including Key Topics in Second Language Acquisition (2014, with Vivian Cook, Multilingual Matters) and Beyond Age Effects in Instructional L2 Learning (2017, with Simone Pfenninger, Multilingual Matters). Larissa Aronin is Associate Professor at the Oranim Academic College of Education, Israel. She has published numerous articles and books on multilingualism, including The Material Culture of Multilingualism (Aronin et al., 2018, Springer) and Multilingualism (Aronin & Singleton, 2012, John Benjamins).