Abstract
The article is devoted to the study of the diachronic development of full-fledged root morphemes into relic root morphemes (RRMs) within the word-formation system of the Turkic languages, using the Kazakh language as a representative example. A relict root morpheme (RRM) is a residual morphemic unit identifiable through synchronic wordformation analysis, which functions as a linguistic sign. The semantics of an RRM in a compound word is determined by the presence of a fullroot morpheme as one of its components, whereas in a derived word, the meaning is maintained through the use of productive affixes. A key theoretical framework for analyzing the process includes the concepts of synchrony and diachrony as introduced by F. de Saussure and further developed by N.D. Andreev, who emphasized the systematic nature of diachrony as a sequence of interconnected synchronies.These theoretical principles serve as the foundation for analyzing root morphemes containing RRMs in the Kazakh language. The analysis draws on historical data from Turkic linguistics, including both scholarly and lexicographic sources, to uncover deep word-formation processes from a diachronic perspective. Language evolution in word formation is understood as a natural transformation of individual words, word groups, or syntactic constructions resulting from communicative and cognitive human activity. Such transformations lead to quantitative and structural changes through phonological and morphological processes, resulting in shifts across the linear hierarchy of linguistic units, including root morphemes, derived and compound words, word combinations, and sentences. These linear transformations may also occur in reverse, via lexical attrition and the breakdown of complex structures, ultimately producing RRMs. This reverse evolution from syntactic constructions to compound words, compound words with RRMs, root morphemes, root morphemes with RRMs, and finally to simple root words.The novelty of the research lies in its first comprehensive analysis of RRMs in the Kazakh language, tracing their development through the diachronic depths of the Proto-Turkic and Old Turkic periods. The study aims to confirm the hypothesis that despite internal structural changes, complex and derived words containing RRMs continue to preserve and perform the nominative function that as core linguistic signs.