Summary
In this paper some theories which see language disorder as having a central role in the genesis of the autistic syndrome are described, and evidence relating to these theories is discussed. It is concluded:
(1) that it is unlikely that the language disorder in autism is either a severe form of receptive-executive developmental dysphasia, or dysphasia combined with visual impairments causing failure to develop visual language systems;
(2) that the language disorder is not a disorder of inner language in the sense of being an impairment of symbolizing processes, nor in the sense of being a global impairment of the acquisition of concepts and conceptual thinking;
(3) that there is no reason to suppose that any one criterial feature of autism (such as language impairment) is primary in the sense of causing other criterial features of autistic behaviour to occur; moreover, defects of communication and inner language are almost certainly cognitive in origin and may only be part of a wide ranging cognitive impairment. Language impairment is not, therefore, likely to prove to be the primary disturbance in autism, though language difficulties are conspicuous and important.