Tom Roeper, Professor of Linguistics at the University of Massachusetts, has studied child language for thirty years, and is a co-author of the Diagnostic Evaluation of Language Variation (DELV), co-editor of Studies in Theoretical Psycholinguistics, and one of the founding editors of Language Acquisition. He has worked on numerous grants from National Science Foundation, National Institutes of Health in the US and other national science foundations in Canada, Europe and Asia. He has lectured all over the world on these topics.