An increasing number of families and professionals are involved with severely communication-impaired children, adolescents and adults who use alternative communication systems to compensate for delayed systems and strategies that can be used to increase the communicative possibilities of people with limited spoken language. The authors discuss factors that are important when choosing communication systems, assessment strategies, environmental adaptation, and the principles for teaching comprehension and use of such communication systems to individuals with different disabilities; including motor impairments, learning disability and autism. This book is unique within the field of augmentative and alternative communication with its basis in modern developmental theories of language and communication, its practical approach with many examples and focus on every-day situations, and its coherent and readable text. It may serve as an introductory text book for speech and language therapists, teachers in school and preschool, psychologists and care nurses, as well as a source of information for families with members who have severe developmental speech and language disorders.