Merrill Swain is a professor emerita of second-language education at the Ontario Institute for Studies in Education, University of Toronto. She developed the output hypothesis. This idea about second-language acquisition says that learners cannot become very good at the grammar of a language only by taking in language and trying to understand it. They must also speak to learn. Swain also worked with Michael Canale on communicative competence. Swain was the president of the American Association for Applied Linguistics in 1998. She received her PhD at the University of California.