The article is devoted to studying the political speeches of Ukrainian presidents (the last decade) at the United Nations (UN), particularly the theoretical and methodological foundations of studying the specifics of political discourse in international communication, namely, in the politico-diplomatic aspect. This study aims to deepen the theoretical understanding of political discourse and reveal the linguistic aspects that determine the communicative nature of political speeches at the UN. In particular, the authors pay attention to the linguistic aspect of politicians' speeches in English at the UN, and conduct a detailed analysis of the axiological language tools used by the Ukrainian presidents to express their assessments and views. The use of specific lexical units that help structure and formulate political ideas, considering the international nature of diplomatic relations, is considered. Understanding the linguistic axiological features of political and diplomatic speech helps to improve communication between representatives of different countries. The study of effective ways of linguistic influence through lexical units with an evocative load can also help to reduce misunderstandings in international relations. This research has used a wide range of scientific methods, including content analysis of the English-language speeches of politicians on the background of political and diplomatic discourse using structural and semantic identification and categorization of lexical features, functional and pragmatic analysis of linguistic means of axiological nature, as well as the method of generalization and systematization to summarize and arrange the information obtained in the course of the study.