The clinical-psychological-pedagogical picture of autistic personality disorders of a child is highly complex and diverse compared to other mental development disorders. The divergence of researchers' views on the autism clinic leads to a scientific discussion on the problem of conceptual and terminological base of definitions and concepts, so, as a consequence, the problem has a conceptual and diagnostic orientation. Summarizing the research of scientists, we highlight the characteristic manifestations of autism in older preschool age: lack of mental activity; violation of the interaction of mental functions; unevenness, partialness of intellectual development; gross violations of purposefulness and arbitrariness of attention; lack of lively interest, interest in the new, environmental research; the tendency to perceive information as if passively absorbing it into whole blocks; the reaction of departure from the influences of the environment directed on the child; adverse reaction or no reaction at all when trying to draw attention to the objects of the surrounding reality; rapid exhaustion and oversaturation with any purposeful activity; difficulty concentrating; difficulties in symbolization, transfer of skills from one situation to another; impaired formation of social and communicative functions. Having analyzed many scientific studies, we can determine the number and variety of speech disorders in children with autistic disorders: challenging to interpret crying; limited barking; lack of imitation of sounds; phonography of speech; mutism; echolalia; words-stamps, phrases-stamps; neologisms; limited use of pronouns; lack of speech in speech; speech autonomy; speech disorders; inability to form words; violation of the semantic, syntactic, grammatical structure of speech; violation of speech melody; violation of prosodic components of speech; inability to engage in dialogue; specificity of the development of monologue speech.