This article analyzes the impact of phonetic-phonematic deficiencies in children's speech on educational activities and the process of literacy formation. It is highlighted that incorrect pronunciation of speech sounds, insufficient development of phonemic perception, and difficulties in differentiating sounds are important obstacles to the formation of reading and writing skills. It also explains the connection of phonetic-phonematic development deficiencies with written speech disorders such as dysgraphia and dyslexia based on scientific sources. The article shows the effectiveness of early detection of speech defects, systematic organization of correctional and speech therapy work, and didactic games and exercises aimed at developing phonemic perception. The importance of speech therapy correction in supporting the speech, cognitive, and communicative development of children is substantiated, and the pedagogical conditions necessary for the successful acquisition of literacy are described.