Historical grammar is now in a position to confirm or to refute. - Michel Bréal

We must realize the extent to which it is necessary that our knowledge of language be based on history. Only history can impart to words that degree of precision which we need in order to understand them well.

There is another kind of studies which distinguished from the sometimes opposed to comparative grammar. It is known under the name of general or philosophical grammar , whose principles and observations were articulated by Port Royal and which deals with the relation of the form of language to the operations of the mind.

In modern society, the meaning of words changes much more quickly than it did in antiquity or even in the recent past. This arises from the intermingling of social classes, the struggle of interests and opinions, the struggle of political parties and the variety of aspirations and tastes.