中古二等韵介音和《切韵》元音数量
The Division ⅱ Medial and the Amount of Vowels in Middle Chinese
中古二等韵有无介音这个问题是近几年讨论的热门话题。
It has been an arguable topic in the past a few years that whether there is a medial of erdengyun .
二等韵