it's the study of how languages change over time.

它研究的是语言的历史变化。

我的专业 - SpeakingMax英语口语达人

Now,that has changed, for sure; but,the centralization of the French government and the domination of Paris over the life of the nation is very difficult to change, over a long period of time.

现在,情况已经发生了改变,但是法国政府的中央集权化,以及巴黎在国民生活中的支配地位,在相当时间段内,都很难得以改变

耶鲁公开课 - 1871年后的法国课程节选

And so, if you rewind the tape and play it again over and over and over again, each time you set things up the very same way they must move or transform or change or end up in the very same state.

所以,如果你将一盘磁带,反反复复地播放,每次你播放的内容,从头到尾的起承转合一定是,绝对一致的

耶鲁公开课 - 死亡课程节选