孝感入声具有紧元音性质，它成为孝感入声由韵母结构范畴向声调范畴转化的桥梁，是一种过渡性质的区别性特征。文章提出，汉语入声的消亡分为三个时期：塞音韵尾期、紧元音期、舒化期。 Xiaogan intonation has the character of tight vowel, which becomes the bridge of Xiaogan intonation transformed from vowel structure category to tone category, which is a distinctive feature of transitional nature. The article suggests that the disappearance of Chinese into the sound is divided into three periods: stop syllable end, tight key sound period, Shu period.