[…] by and by his mind [child] has grown up, perhaps, to the full measure of that which his speech represents, and begins to exhibit its native and surplus force; it chafes against the imposed framework of current expression; it modifies a little its inherited instrument, in order to adapt better to its own purposes.
- Whitney (1875), Pag. 34-35

An acquired language is something imposed from without upon the methods and results of mental action. It does, indeed, as a frame-work imposed upon a growing and developing body, gives shape to that which underlies it, determining the “inner form;” and yet it is everywhere loose and adjustable.
- Whitney (1875), Pag. 30

Every single language has […] its own peculiar framework of established distinctions, its shapes and forms of thought, into which, for the human being who learns that language as his “mother-tongue”, is cast the content and product of his mind, his store of impressions, however acquired, his experience and knowledge of the world.
- Whitney (1875), Pag. 21-22