Betty J. Birner

Richard A. Spears, Ph.D.is a former Professor of Linguistics at Northwestern University, and a highly respected lexicographer and author in the field of ESL reference.Steven R. Kleinedleris a specialist in linguistics and lead author of The American Heritage Science Dictionary.Betty J. Birner, Ph.D.is a professor at the Institute for Research in Cognitive Science at the University of Pennsylvania.Luc Nissetis an experienced illustrator and author of language learning materials.