The aim of the study is to reveal the correlation between the speech development level of 4-7 year old children and their reading skills mastering. 151 children are involved in the investigation. Complex approach includes acoustical, phonetic and linguistic analyses of children speech, assessment of reading skills mastering, the definition of phonemic hearing, the functional asymmetry of the behavioral tests and electrophysiological brain activity. Our data show correlations between the child age, mastering of reading skills, the level of speech development, functional sensory-motor asymmetry and parameters and alpha-rhythm localization in electroencephalogram.