The article is devoted to the problem of spelling adaptation of the words borrowed from the Russian language in the Yakut language. The aim of the research is to analyze the peculiarities of the Russian consonants transmission in the beginning of borrowed words by means of the Yakut language. The study is based on the material extracted from modern lexicographic sources: published volumes of “The Big Explanatory Dictionary of the Yakut Language” and “Spelling Dictionary of the Yakut Language.” The theoretical basis for the study are the methodological provisions of N. D. Dyachkovskiy on the description of the system of Yakut language consonants. The main methods of work are the continuous sampling method, lexicographic analysis method, descriptive method. The results of the analysis of spelling changes of Russisms that have undergone phonetic development are presented. It is shown that at the stage of adaptation, the stems of borrowings can maintain the original spelling or undergo various transformations in accordance with the principles of writing, prevailing in the theory and practice of Yakut writing. The author explains that the changes are determined by the difference in the phonetic systems of the Russian and Yakut languages. The obtained results can be used in the practice of compiling “The One-Volume Explanatory Dictionary of the Yakut Language.”