Children with special educational needs have always attended mainstream schools, and teachers since the dawn of time have differentiated their approaches to suit children with different aptitudes, interests and learning problems. Some children will be relatively clear cut, but many children may have more than one underlying condition or several educational needs arising from the primary condition. There is a strong association between communication problems and subsequent learning, behavioural and emotional difficulties. A firm foundation in communication is needed for children to achieve their potential in both social and academic spheres. Communication and language involve many different processes. Communication involves every aspect of Children: hearing, seeing, feeling, moving, thinking, remembering, predicting, inferring, imagining, empathising, decision making, and articulating. Autistic spectrum disorders (ASD) are associated with fundamental difficulties in communication, understanding other people's emotions and social conventions. Children with ASD may have moderate or severe learning difficulties, but around one third function cognitively within the normal range.