He is the co-author of A Frequency Dictionary of Contemporary American English (Routledge, 2010). About the SeriesRoutledge Introductions to Applied LinguisticsRoutledge Introductions to Applied Linguistics is a series of introductory level textbooks covering the core topics in Applied Linguistics, primarily designed for those beginning postgraduate studies, or taking an introductory MA course as well as advanced undergraduates. Titles in the series are also ideal for language professionals returning to academic study.