The Historical Change of the Vowels а/ә/е in Turkic Languages

The history of Turkic sounds is the history of the phonetic structure and phenomena system of the contemporary language. Historical phonetics aims at explicating the ways of contemporary sound formation, the structure of the phonetic system and the development of its tendencies. The article focuses on the historical development of the phonemes а, ә, е in Turkic, namely in Kazakh linguistics. While the mentioned sounds were identified historically in the works of Turkologists, the formation of ә and е is approached differently. Based on certain research data, the vowel ә is considered a sound borrowed from Arabic and Persian. Other scholars identify the vowel ә as the sound originating in the ancient Turkic language or view it as a sound formed between ә and е. From this standpoint, the issue of identifying the phonemes ә and е based on scientific data becomes crucially relevant. In this regard, the peculiarities of the local usage of the vowel phoneme ә and the language data accompanying the sounds а/ә are examined. Apart from this, the historical change of the phonemes а/ә/е is scrutinized according to the conceptions of scholars. The vowel content of the Kazakh language is described based on scientific data. The study justifies the existence of nine vowel phonemes in the Kazakh language and identifies the vowels ә and е from the historical viewpoint.