Importance. The problem of the formation of a multilingual student’s personality is important and relevant for modern language education. The purpose of the study is to propose a technology for the formation of multilingual skills of schoolchildren (grades 5-9) based on a modular general development program for the study of languages and cultures in an additional training course.Research Methods. Based on scientific literature theoretical analysis, the refined concept of “modular general educational program of additional education” as a means of multilingual skills forming of schoolchildren is presented. It is proved that a prerequisite for the multilingual skills formation of schoolchildren is their awareness of the value of their multilingual development, upbringing and development of a multilingual personality based on mastering socially significant experience, which is embodied in language knowledge and skills, language and speech activity. The main methods of polylinguistic skills’ formation are: comparative, communicative, method of control and self-control.Results and Discussion. It is revealed and substantiated that the use of a modular general development program in an additional training course will allow developing the student’s multilingual personality, its linguistic thinking, and language ability, which arouses great interest in the didactic possibilities of the proposed technology.Conclusion. The application of the research results can contribute to the development of new directions in linguodidactics and the design of an effective multilingual school environment.