Abstract: The subject of this research is the analysis of peculiarities of the Russian language as an important element of interethnic relationships in polyethnic modern society. The article examines such terms as “language” and “native language”, determines the main theories of origin of the language, as well as the specificities of sociological study of bilingualism. The authors underline the relevance of studying the Russian language along with the attention of our multiethnic country to the problems of its preservation and development; as well as note certain specificities of the language policy of the Russian Federation and its major objectives. The questionnaire survey of the population, conducted in 2016 in the thirty one region of the Russian Federation, became the key method of this sociological research. The article provides the comparative analysis of indicators of the literacy of population of different age groups in the national, monoethnic, and polyethnic regions of Russia. The authors list the characteristic features of the Russian language, and major issues regarding functioning. The conclusions may be valuable for the researchers dealing with the questions of interethnic relationships, and the Russian languages as its basis.