There is no discernible instinctive basis in human speech as such, however much instinctive expressions and the natural environment may serve as a stimulus for the development of certain elements of speech [...]
- Sapir (1921), a pag.8

[...] language can but be the outward facet of thought on the highest, most generalized, level of symbolic expression.
- Sapir (1921), a pag.15

The auditory centers alone may be excited; or the impulse to linguistic expression may be communicated as well to the motor nerves that communicate with the organs of speech but be inhibited either in the muscles of these organs or at some point in the motor nerves themselves.
- Sapir (1921), a pag.18

The fundamental groundwork of language -the development of a clear-cut phonetic system, the specific association of speech elements with concepts, and the delicate provision for the formal expression of all manner of relations- all this meets us rigidly perfected and systematized in every language known to us.
- Sapir (1921), a pag.22

[...] if 'sing' were [...] the fixed expression of the unmodified concept, there should be no room for such vocalic aberrations as we find in 'sang' and 'sung' and 'song', nor should we find sing specifically used to indicate present time for all persons but one (third person singular 'sings').
- Sapir (1921), a pag.27

[...] linguistic history shows conclusively that sooner or later the less frequently occurring associations are ironed out at the expense of the more vital ones. In other words, all languages have an inherent tendency to economy of expression.
- Sapir (1921), a pag.38

[...] the incidental expression of desire and emotion are, for the most part, alien to linguistic expression.
- Sapir (1921), a pag.41