The article is devoted to the research of the hearing-speech memory as the basic modality of the mnemonic processes necessary for successful reading skills mastering. In particular, we trace the correlation between the non-formation of a number of mental processes and obstacles in the perception and active processing (decoding) of information for elementary schoolchildren. We see that impaired memory greatly impacts the mastering of the reading skill for children with a specific disorder of psychological development. The normative indexes of hearing-speech memory were obtained, its qualitative and quantitative characteristics were determined for the younger students with Dyslexia.