The specificity of speech disorders in primary school children with intellectual disorders is determined primarily by the peculiarities of higher nervous activity and mental development. Speech disorders within intellectual disorders in the psycholinguistic focal area have been little studied. The functional system of language and speech was chosen as the basis for the psycholinguistic research of speech of the selected category of children i. e. a functional self-organizing system that creates basic psychophysiological support for communicative and speech activity. Its system-forming factor is the general task and result i. e. the generation of utterances in the process of speech communication. The purpose of the article is to substantiate the psycholinguistic study on determining the peculiarities of speech disorders of primary school children with intellectual disorders; to describe its qualitative and quantitative indicators. The leading research methods were the observation of speech of the selected category of children, analysis of audio recordings of their utterances, linguostatic processing of quantitative data, generalization of the obtained qualitative and quantitative indicators during the survey. The results of the research revealed the dominance of medium and low levels of development of subsystems of the functional system of language and speech in junior high school students with mild mental retardation and low and extremely low (initial) levels in junior high school students with moderate degree. Based on the results of psycholinguistic research, the variants of speech dysontogenesis in intellectual disorders of children were determined. The results of the research also showed significant violations of the development of basic indicators of the functional system of language and speech at the level of all its subsystems: speech perception; speech comprehension as a thought-mnemonic process, modelling of speech comprehension and generation of speech. It was found that intellectual disorders have a specific impact on the nature of speech disorders.Keywords: Speech Activity, Intellectual Disorders, Functional System of Language and Speech, Children with Special Educational Needs.