Jean Berko Gleason, PhD. is one of the world's leading experts on children's language and one of the founding mothers of the field of psycholinguistics. She created the famous "Wug Test," which reveals how children learn the rules of language, such as how to make singular words plural. Her current work investigates parents' speech and the interactive nature of language acquisition. She is the author of leading textbooks in her field and many influential studies of aphasia, language development, gender differences in language, and language in the Roma community in Hungary. Dr. Berko Gleason is Professor Emerita in the Department of Psychological and Brain Sciences at Boston University. A member of the Academy of Aphasia, she is past president of the International Association for the Study of Child Language and of the Gypsy Lore Society, and a Fellow of the American Association for the Advancement of Science (AAAS). Her classic work in child language development is frequently cited in the professional literature and featured in the popular media. She is a featured scientist in the award-winning PBS online Nova Science Now series The Secret Life of Scientists. Nan Bernstein Ratner, Ed.D., C.C.C. is Professor, Department of Hearing and Speech Sciences, University of Maryland at College Park and participating faculty in the Maryland Language Sciences Center and Program in Neuroscience and Cognitive Neuroscience, and a Board-Recognized Specialist in Child Language and Language Disorders. Dr. Bernstein Ratner is the editor of numerous volumes, and author of numerous chapters and articles addressing language acquisition and fluency in children. Many of her research reports can be found in the Journal of Speech and Hearing Research and other major journals, with chapters in major texts on child speech and language development. With Jean Berko Gleason, Dr. Bernstein Ratner is the author of the text Psycholinguistics as well as prior editions of The Development of Language. In 2014, Dr. Bernstein Ratner received the Honors of the American Speech-Language Hearing Association; she was made a Psychology Fellow of the American Association for the Advancement of Science (AAAS) in 2015.