Every period of linguistic life, with its constantly progressing changes of form and meaning, wipes out a part of the intermediates which connect a derived element with its original.
- Whitney (1875), a pag.125

The individual learns his language, obtaining the spoken signs of which it is made up by imitation from the lips of others, and shaping his conceptions in accordance with them. It is thus that every language is maintained in life; if this process of tradition, by teaching and learning, were to cease in any tongue upon earth, that tongue would at once become extinct. But this is only one side of the life of language. If it were all, then each spoken dialect would remain the same from age to age.
- Whitney (1875), a pag.32