Helpful comments on drafts of this book were received from the following individuals: Allyssa McCabe, Joy James, Ruth Bahr, Arthur Guilford, Jane Scheurle, Lynda Campbell, David Bloome, and Christine Probes. In addition, I would like to thank the reviewers commissioned by Lawrence Erlbaum Associates: Sonja L. Lanchart, University of Georgia, Denise Troutman, Michigan Sate University and two anonymous reviewers, your comments were very helpful in my revision of the book. I would also like to thank Susan Friedman and Laurel Jaffer for their editorial work on this book. Thanks to Naomi Silverman for her valuable feedback and encouragement throughout the process of writing this book. The writing of this manuscript was supported by funds fiom the National Institute on Deafness and other Communication Disorders (KO1 DC00160 04).