“(We may add that it was Saussure who introduced the term ‘coefficient’ [into linguistics], and we may note at the same time that Saussure also introduced another term into linguistics, one that has found high favor with linguists, namely, the term ‘phoneme’…. He introduced it, for lack of a better word, as designation for the expression elements of a language in order to avoid confusion with the ‘sounds’ of linguistic usage—that is, to designate the purely ‘algebraic entities’ of his theory. By an irony of fate, Saussure’s theory was so basically misunderstood by his contemporaries and by many who came after them that the term is now generally used as a synonym for ‘linguistic sound’—precisely what Saussure was trying to avoid.)”
Hjelmslev - Language: An Introduction, p. 125