I would like to thank Robert DeKeyser, Professor of Second Language Acquisition, University of Maryland, for agreeing to be interviewed for these working papers. Dr. DeKeyser’s research interests include SLA, interlanguage variability, individual differences in SLA, aptitude-treatment interaction, cognitive psychology of language acquisition, and age effects in SLA. He came to Michigan State University to give a plenary talk at the Second Language Research Forum 2009. The interview was conducted by Jimin Kahng on November 1, 2009. For more information about Dr. DeKeyser, please visit his faculty page: http://www.languages.umd.edu/SLAA/rdk.html.