Pre- press version Published in: Aronin, Larissa (2019). What is Multilingualism? In David Singleton and Larissa Aronin (eds.), Twelve Lectures in Multilingualism. (pp. 3- 34). Bristol: Multilingual Matters. http://www.multilingual-matters.com/display.asp?isb=9781788922050. Part 1 Multilingualism in Society and Education