This paper is an investigation of the acoustic characteristics of vowels in three Altaic languages: two Mongolic languages, Western Buriat (WB) and Tsongol Buriat (TB), and a Tungusic language, Ewen. Based on the formant frequencies of simple vowels in initial syllables, we first demonstrate that all the three languages can be best described as having a tongue root (TR) contrast-based vowel system. Using various acoustic measures such as F1, F2, normalized A1-A2, B1, and center of gravity, we then compare the two vowels in each harmonic pair in search of the acoustic correlates of the RTR contrast in Altaic languages. The results show an overall resemblance to the previous acoustic findings of the ATR contrast in West African languages. F1 successfully distinguishes all vowel pairs in all the three languages. B1 and the center of gravity also differentiate most vowel pairs. However, the distinction in the values of normalized A1-A2 is observed only in WB, not in the other two languages TB and Ewen.

Keywords: tongue root contrast, ATR, RTR, Altaic, Buriat, Ewen, F1, normalized A1-A2, B1, center of gravity