[...] even the most difficult mathematical proposition is inherently dependent on an arbitrary set of symbols, but it is impossible to suppose that the human mind is capable of arriving at or holding such a proposition without the symbolism.
- Sapir (1921), a pag.15

[...] the sentence, has [...] a psychological as well as a merely logical [...] existence. [...] It is the linguistic expression of a proposition. It combines a subject of discourse with a statement in regard to this subject.
- Sapir (1921), a pag.35

It is much better frankly to recognize the fact that either or both of the [...] terms of the sentence-proposition may be incapable of expression in the form of single words.
- Sapir (1921), a pag.36

In some languages [...] the suffixes alone relate the word to the rest of the sentence, the prefixes being confined to the expression of such ideas as delimit the concrete significance of the radical element without influencing its bearing in the proposition.
- Sapir (1921), a pag.68

No proposition, however abstract its intent, is [...] possible without a tying on at one or more points to the concrete world of sense. In every intelligible proposition at least two of these radical ideas must be expressed [...]
- Sapir (1921), a pag.93

[...] relational concepts must be expressed as moor the concrete concepts to each other and construct a definite, fundamental form of proposition.
- Sapir (1921), a pag.93

The more synthetic the language [...] the more clearly the status of each word in the sentence is indicated by its own resources, the less need is there for looking beyond the word to the sentence as a whole. The Latin 'agit' '(he) acts' needs no outside help to establish its place in a proposition.
- Sapir (1921), a pag.109

It is well to remember that speech consists of a series of propositions. There must be something to talk about and something must be said about this subject of discourse once it is selected.
- Sapir (1921), a pag.119