This book provides a practical guide to the use of Metaphon therapy, the principled approach to phonological therapy, which takes full account of theories of learning and the linguistic nature of phonological disorder in children. The authors explore clearly the theoretical back-ground to Metaphon and translate it into clinical practice. For this second edition the book has been extensively revised and expanded to take account of current research and literature on phonological disorder and linguistic awareness and advances in the development of Metaphon.