The psychology of a language ...

The psychology of a language which, in one way or another, is imposed upon one because of factors beyond one's control, is very different from the psychology of a language which one accepts of one's free will.
 Edward Sapir

Quotes from the same author

What fetters the mind and benumbs the spirit is ever the dogged acceptance of absolutes.
 Edward Sapir
English, once accepted as an international language, is no more secure than French has proved to be as the one and only accepted language of diplomacy or as Latin has proved to be as the international language of science.
 Edward Sapir
Comparison of statements made at different periods frequently enable us to give maximal and minimal dates to the appearance of a cultural element or to assign the time limits to a movement of population.
 Edward Sapir
A common allegiance to form of expression that is identified with no single national unit is likely to prove one of the most potent symbols of the freedom of the human spirit that the world has yet known.
 Edward Sapir