AbstractThe research explores the issues related to study the effects of bilingualism on cognitive development in preschool children, identifying the most common challenges they face and suggesting a technology for developing preschoolers’ bilingual communicative competence. The study is based on fundamental ideas of sociocultural studies devoted to the role of learning environment in child development of cognition, emotion, imagination and creativity. We conducted the study in the Republic of Tatarstan (region in Russia), which is populated mainly by Tatars and Russians. One hundred sixty-five preschoolers (5-7 years old) took part in the survey. Cognitive differences and communicative competence between monolinguals and bilinguals were taken into account. Measures of executive functions were employed. Preschool teachers filled in observation cards. The study confirms that bilingual children are distinguished by cognitive abilities, in particular, peculiar "flexibility" of thinking, intellectual lability and non-standard approach to processing information of different levels. Monolinguals have a large lexical reserve and productivity of speech activity. Thus, a specialized educational environment with the features of in-depth foreign language learning is defined as a system of conditions created in order to achieve a specific level of a foreign language communicative competence including prerequisites for personal and cognitive development at a younger age.