"Language is a system of signs that express ideas, and is therefore comparable to a system of writing, the alphabet of deaf-mutes, symbolic rites, polite formulas, military signals, etc. But it is the most important of all these systems.
<i>A science that studies the life of signs within society</i> is conceivable; it would be part of a social psychology and consequently of general psychology; I shall call it <i>semiology</i> (from Greek sēmeîon 'sign'). Semiology would show what constitutes signs, what laws govern them. Since the science does not yet exist, no one can say what it would be; but it has a right to existence, a place staked out in advance. Linguistics is only part of the general science of semiology; the laws discovered by semiology will be applicable to linguistics, and the latter will circumscribe a well-defined area within the mass of anthropological facts." p16
"The linguistic sign unites, not a thing and a name, but a concept and a sound-image. The latter is not the material sound, a purely physical thing, but the psychological imprint of the sound, the impression it makes on our senses. The sound-image is sensory, and if I happen to call it "material," it is only in that sense, and by way of opposing it to the other term of the association, the concept, which is generally more abstract." p66
"Signs that are wholly arbitrary realize better than the others the ideal of the semiological process; that is why language, the most complex and universal of all systems of expression, is also the most characteristic; in this sense linguistics can become the master-pattern for all branches of semiology although language is only one particular semiological system." p68
"<p>The two parts of linguistics respectively, as defined, will be the object of our study.
</p><p><i>Synchronic linguistics</i> will be concerned with the logical and psychological relations that bind together coexisting terms and for a system in the collective mind of speakers.
</p><p><i>Diachronic linguistics</i>, on the contrary, will study relations that bind together successive terms not perceived by the collective mind but substituted for each other without forming a system.
"<p>But here is the paradox: on the one hand the concept seems to be the counterpart of the sound-image, and on the other hand the sign itself is in turn the counterpart of the other signs of language.
Language is a system of interdependant terms in which the value of each term results solely from the simultaneous presence of the others, as in the diagram:
"In the syntagm a term acquires its value only because it stands in opposition to everything that precedes or follows it or to both." p123