Language development is delayed in most children on the autistic spectrum. The children are dysphasic as well as autistic. Comprehension and pragmatics are invariably affected. Lower level mixed receptive/expressive disorders involve phonological and syntactical processing, whereas higher level processing disorders involve semantics and formulation of discourse. In some children, lower level disorders may be so severe as to preclude speech, whereas in others phonology may be deficient in spontaneous production but not in repetition. Abnormal features of autistic language include aberrant prosody, immediate and delayed echolalia (scripts), and perseveration. Electrophysiological studies indicate that brainstem-evoked potentials are normal. Even in fully verbal individuals with autism, early and late cortical components of auditory, but not visual, event-related potentials are abnormal. Appropriate intervention must address language and behavioral issues. In children with severely defective auditory language, provision of visual language to supplement speech is essential.