Introduction. The right to judicial protection in one's native language ensures the adversarial nature and transparency of civil proceedings and serves as a guarantee and embodiment of all procedural actions in the administration of justice. However, the system-forming influence of the principle of the state language on the course of legal proceedings is somewhat underestimated in modern judicial practice. Procedural legislation also contains uncertainties and limitations regarding the preservation of cultural identity in terms of ensuring access to justice. Theoretical analysis. In modern academic doctrine, the principle of the state (national) language is viewed as a guarantee of the effective administration of justice for the purpose of maintaining equality of parties in a multinational state. However, this study revealed that maintaining the legal guarantees for choosing one’s native language when applying to court and during civil proceedings depends largely on judicial discretion, with the criteria for applying this discretion not being defined in this case. Specifically, it was found that judges do not always have sufficient competence to determine the parties’ command of Russian or the interpreter’s qualifications. Furthermore, procedural law significantly limits the conduct of legal proceedings and office work in the language of a constituent entity of the Russian Federation. Empirical analysis. It has been revealed that the implementation of the state language principle remains unresolved in contemporary Russian procedural legislation and judicial practice. The complexity and unpredictability of the grounds for appointing an interpreter and transitioning to a civil case in another language reduce access to justice and guarantees of an adversarial judicial process. Results. The article demonstrates that the trinity of “publicity, adversarial proceedings, and the language of legal proceedings” cannot function in isolation. It is concluded that it is advisable to create a comprehensive state program to identify issues related to the use of native languages in interactions with government agencies and the judiciary. Judicial competence to establish rules for conducting legal proceedings, including those related to the choice of the language of legal proceedings, must be exercised at the stage of preparing a case for a trial.