The manual is devoted to one of the complex and underdeveloped problems of speech therapy - impaired perception of oral speech and their correction in preschoolers with mental retardation (MPD). The manual outlines modern ideas about the process of perceiving oral speech, about the structure of a speech defect and the features of understanding speech by children with this form of mental dysontogenesis. Diagnostic techniques are proposed to identify speech perception disorders, as well as a methodology for speech therapy work on the development of perception of oral speech by preschoolers with mental retardation. It is intended for practical speech therapists and defectologists, students of the faculties of correctional pedagogy. Can be used by parents of children with developmental problems.