The article is devoted to the difficulties of mastering and errors in the use of foreign words in oral and written business (office) communication in Russian. The relevance of this topic is explained by the special speech responsibility of representatives of socially significant professions who use Russian as the state language, as well problems arising in the implementation as of the provisions of the Federal Law “On the State Language of the Russian Federation” as amended on February 28, 2023. The article substantiates the thesis about the need to take into account not only the lack of Russian analogues, but also other factors when using borrowed words. Of great importance for collecting language material was the author’s many years of work experience at the Faculty of Additional Education at the North-Western Academy of Public Administration (now the North-Western Institute of Management of the Russian Academy of National Economy and Public Administration under the President of the Russian Federation), in the executive authorities of Saint Petersburg and North-West Russia, in the Interregional Resource Center under the Administration of the Governor of Saint Petersburg. Theoretical methods (analysis, synthesis, historicism) made it possible to identify subjective and objective difficulties in mastering, typical errors in the use of borrowed words, as well as update ways to overcome them, which can be of practical importance for the conscious implementation of this law and improving the culture of Russian business (official) speech.