All sustainable deviations of the speech system of the children with normacusis but without primary intellectual disabilities are severe speech disorders. Children need different types of correction depending on symptoms and etiology of speech disorders, the success of correction depends largely on the correct diagnosis. Currently, the choice of corrective programs aimed at the development of damaged brain structures is relevant nowadays. The purpose of the study is to determine the potential use of electroencephalography (EEG) indicators for early diagnosis of serious speech disorders and understanding of the correction activities and methods to be used in the work of a speech therapist. There have been many laboratory studies related to the functional activity of the brain but the electroencephalogram, as a means of diagnosing preschool children suffering from severe speech disorders, is becoming increasingly important. The EEG studies the regularities of the total electrical activity of the brain; The EEG is a method of graphical registration of the brain biopotentials, which allows analysing its physiological maturity and the presence of focal lesions, the nature of general brain disorders. The speech therapist studies activities only of the peripheral part of the speech apparatus, consequences caused by disorders of the central nervous system (CNS) of the brain, to be more precise. Thus, if the speech therapist has additional information about the function of the central parts of the brain when working with a child, this will help the specialist in choosing the most effective program for correcting disorders. Our research has shown that children’s speech disorders are not an only pathology, they are often combined with other disorders of the nervous system and child’s altered psycho-emotional status. The EEG analysis of the children suffering from speech disorders indicates the presence of pathological electrical activities of various degrees. This is consistent with the results of the studies dealing with higher mental functions which reveal their significant changes when having severe speech disorders. Understanding the neurophysiological mechanisms enabling the organisation of speech activities is a necessary condition for the development and application of adequate methods aimed at correcting speech disorders. The use of the electroencephalographic research reveals speech disorders by assessing the compliance of the electrical activities of the cerebral cortex and trunk with age-related norms. The study of the neurophysiological mechanisms that cause difficulties in developing children’s speech will help in the future to develop programs for special psychological and pedagogical correction.