The article analyzes the scientific contribution of Professor K. Zhubanov to the formation and development of the Kazakh language: the conversion of the Kazakh alphabet and spelling rules, the transition of the Kazakh alphabet to Latin, the formation of Kazakh terminology, the compilation of the first Kazakh scientific textbooks, etc. Various aspects of the Kazakh language were considered by the scientist from a scientific point of view. In order to identify and reflect the natural laws of the Kazakh language, K. Zhubanov conducted an in-depth analysis of the grammatical, phonetic and lexical features of Kazakh words, as well as the laws of their historical development. In this article, various scientific works of the Professor, devoted to the issues of Kazakh linguistics, have been studied in detail: "Lecture courses on the Kazakh language", "Textbook on the Kazakh language grammar", "Kazakh language program", "New grammar", "Spelling and grammar rules of the Kazakh language” (Letter to Zhangazy), “From the history of the Slavic language in the Kazakh language”, “Booklet on a book and a folded book”, “Formation of the Kazakh book language”, “The form of the booklet in the Kazakh language”.