高本汉将中古庚韵的主元音拟为舌面次低央元音,在重唇音有一个i介音加央后元音就会演变成轻唇音的说法被支持后,中古庚韵的主要元音需要被改动成舌面展唇低前元音。重唇音变成轻唇音还有“三等合口”这另一个条件说,本文以为“三等合口”的说法在本质上与“i介音加央后元音”并无二致,所以庚韵主元音的拟音仍是维持舌面次低央元音。 Gao Ben Han will be the ancient Geng Yun vowels as the main vowels of the second lowest central vowel, heavy lip sounds have an i-mediated Canadian Central Vowels will evolve into a light lip sound is said, after the main Geng Yun main element Tone needs to be changed into a low front vowel with lingual lip. Heavy lip sound into a light lip sound There are other conditions, this article said that "triple equivalent Second, so Geng Yun main vowel tone is still to maintain the tongue surface times vowels.