“The habitual association of radical elements, grammatical elements, words, and sentences with concepts or groups of concepts related into wholes is the fact itself of language. It is important to note that there is in all languages a certain randomness of association. Thus, the idea of “hide” may be also expressed by the word “conceal,” the notion of “three times” also by “thrice.” The multiple expression of a single concept is universally felt as a source of linguistic strength and variety, not as a needless extravagance. More irksome is a random correspondence between idea and linguistic expression in the field of abstract and relational concepts, particularly when the concept is embodied in a grammatical element. Thus, the randomness of the expression of plurality in such words as books, oxen, sheep, and geese is felt to be rather more, I fancy, an unavoidable and traditional predicament than a welcome luxuriance. It is obvious that a language cannot go beyond a certain point in this randomness. Many languages go incredibly far in this respect, it is true, but 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. Were this tendency entirely inoperative, there would be no grammar. The fact of grammar, a universal trait of language, is simply a generalized expression of the feeling that analogous concepts and relations are most conveniently symbolized in analogous forms. Were a language ever completely “grammatical,” it would be a perfect engine of conceptual expression. Unfortunately, or luckily, no language is tyrannically consistent. All grammars leak.”
—Edward Sapir 1921, 39; my emphasis.