The communications problems of autistic children vary to some degree and may depend on the intellectual and social development of the individual. Some may be completely unable to speak whereas others have well-developed vocabularies and can speak at length on topics that interest them. Any attempt at therapy must begin with an individual assessment of the child's language abilities by a trained speech and language pathologist.

Though some autistic children have little or no problem with the pronunciation of words, most have difficulty effectively using language. Even those children who have no articulation problems exhibit difficulties in the pragmatic use of language such as knowing what to say, how to say it, and when to say it as well as how to interact socially with people. Many who speak often say things that have no content or information. Others repeat verbatim what they have heard (echolalia) or repeat irrelevant scripts they have memorized. Some autistic children speak in a high-pitched voice or use robotic sounding speech.

Two pre-skills for language development are joint attention and social initiation. Joint attention involves eye gaze and referential gestures such as pointing, showing and giving. Children with autism lack social initiation such as questioning, make fewer utterances and fail to use language as a means of social initiation. Though no one treatment is found to successfully improve communication, the best treatment begins early during the preschool years, is individually tailored, and involves parents along with professionals. The goal is always to improve useful communication. For some, verbal communication is realistic; for others, gestured communication or communication through a symbol system such as picture boards can be attempted. Periodic evaluations must be made to find the best approaches and to reestablish goals for the individual child.