SUMMARY
The number of senior preschoolers with speech development below the norm on the eve of school education is growing steadily annually. Updating the educational process organization, aiming at improving the efficiency and quality of primary school students education and, consequently, growing requirements for the level of their knowledge and skills, on the one hand, and the increase of the number of children with speech impairment, on the other, necessitate propedeutics of impairment and the development of special diagnostic tools.In this paper, we set an objective to analyze the reasons for which younger primary school students have difficulties in the process of written speech formation. The research is aimed at studying the level of the formation of basic processes and functions essential for literacy and writing skills acquisition.240 primary school students were engaged in a pilot experiment aimed at assessing the efficiency of speech therapy screening. The traditional screening methods have always been the observation, conversation, but one of its modern methods is testing. The analysis of the results of the younger primary school students' frontal examination enables to state that in students from 1st to 4th grades there prevailed average level of formation of basic prerequisites and skills essential for writing skills teaching. According to the results of the study, we can affirm that the study of the degree of the formation of processes and functions essential for literacy and writing skills acquisition by means of speech therapy screening is an essential prerequisite of a comprehensive correction of the speech development of younger primary school students with dysgraphia, as it facilitates early identification of children from "risk groups" and those who have impairments of basic writing skills formation.