This study examines the vocalism of the Toles (Сholushman) dialect in comparison with the Altai-kizhi dialect and the Altaic literary language. The carriers of the Toles (Сholushman) dialect live compactly in the settlements of Balykcha, Koo of the Cholushman Valley, located on the southern coasts of the Teletskoye Lake. The phonetic structure of the Ulagan dialect in general and the Toles (Сholushman) dialect in particular were not the object of a special study before. In Altai linguistics and more widely - in turkology, the system of vowels of Toles (Сholushman) dialect is considered for the first time. For the first time the vocalism of this dialect is analyzed in comatative aspect. The topic is also relevant because the phonetic structure of an unknown language reveals, opening new directions in Altaic linguistics, introducing new material into Turkic science. According to the results of our research, the Ulagan dialect of the telengit language is divided into six dialects. Among them stands Toles (cholushman) dialect. Unlike the Altai language, in the Toles (Cholushman) dialect, in addition to the usual eight short vowels and their long correlates, a specific vowel sound of the mixed series [ä] and its long correlate are used. A specific feature of the Cholushman dialect, which distinguishes it from the Altai language, is the presence of diphthongs. The subject of this study are the short vowels of the Toles dialect. Short broad vowels in the Toles dialect are broader than in the Altai language; the labial vowels are more obliterated than in the Altai language. Comparative analysis by the subjective-auditory method made it possible not only to identify both the general features of the Toles (Cholushman) dialect with Altai-kizhi dialect and Altaic literary language, but also significant differences due to the articulatory and acoustic base of ethnoses.