The article examines the vocabulary (according to the materials of lexicographic works), lexical usage and semantics, semantic structure of polysemantic words and linguistic-semantic features that indicate the integrity of the Turkic world. The national composition of the modern Turkish population, attempts to learn Kazakh and Turkish languages, the degree of names and spelling, the same meaning or the same meaning of names in the Kazakh and Turkish languages, and degrees of discrepancy (mismatching), among them the question of which language is used by residents of the region in priority order is considered. The aim of the article is to determine the amount of common vocabulary in the Kazakh and Turkic languages and to conduct a comparative study of their meanings, to identify the difficulties arising in teaching the two languages as the foreign language words whose meanings are changed, to show the Turkic basis of common vocabulary, to analyze the change of meaning using comparative and historical method. The scientific significance and practical of the article lie in the fact that the linguistic data, evaluation (prediction) of some words in the past and future in a practical sense, the availability of conclusions, the validity and scientificity of judgments and conclusions were not previously known, and if they were known, they were collected in practice and analyzed in a scientific sense as a special object of research. As a result of the research, in order to study lexical-semantic processes in related languages, it is necessary to consider them in comparative and historical-comparative aspects.