The article considers one of the most important issues of vowel harmony of the syllable in the Kazakh and Turkic languages. Actual problems of studying the phonetic structure of the Kazakh language consist mainly in determining the types of syllabic structures and their sound composition. Although the syllable has a special place in the structure of the language, its articulatory nature is poorly understood. Therefore, it should be noted that the solution to the problem of syllables, as one of the language units, lies in the issues of articulation. Researchers have a common opinion about the syllable problem in linguistics, but there is much debate about the definition of syllable types in the Kazakh language. The phonetic and phonological nature of the syllable in the Kazakh language, the function of the syllable in the language and the problems of the syllable have not yet been examined in detail. Based on the research of A. Zhunusbek, M.Isaev, S. Myrzabekov, an analysis of the basic ideas about the nature of the syllable and their limitations is made. The opinions of scientists were studied on the typological common feature of the Kazakh syllable, uniting related languages, and the typological distinctive feature that distinguishes unrelated languages.