The article discusses the results of a study of the relationship between executive functions (inhibitory control, cognitive flexibility, working (speech and visual) memory and the development of Russian speech in children with natural bilingualism and monolinguals in older preschool age. The study involved 63 preschool children (50.8% - boys) aged from 5.6 to 7.3 years (M = 6.42, Med = 6.4) from preschool institutions of Izhevsk (Udmurt Republic). The sample included 31 children with natural bilingualism (Udmurt/Russian language) and 32 monolinguals (Russian language). Standardised methods in the Russian-language version were used to identify the executive functions: the method of verbal-colour interference of by J. Stroop (inhibitory control), the method of studying the learning ability by A.Y. Ivanova (cognitive flexibility) and the test tasks Speech Memory and Visual Memory (working memory). The level of speech development was measured using the test tasks Speech Antonyms, Speech Classifications and Arbitrary Mastery of Speech developed by L.А. Yasyukova. The following mathematical statistics methods were used: descriptive statistics, Mann - Whitney U-test and Spearman rank correlations. According to the results of the study, the facts of the advantages of bilingualism in older preschool age in executive functions, in particular, in inhibitory control cognitive flexibility and speech memory were confirmed. At the same time, no general patterns were determined in the development of Russian speech (L2) in connection with the development of the executive functions of bilingual children: this is explained by the individualisation of the processes of linking the components of speech activity in the second language and cognitive control. In monolingual preschoolers, the speech development in their native language (L1) is associated with the formation of higher mental (executive) functions and the development of the ability to control information processing.