Language is a system whose parts can and must all be considered in their synchronic solidarity. - Ferdinand de Saussure

The characteristic role of language with respect to thought is not to create a material phonic means for expressing ideas but to serve as a link between thought and sound, under conditions that of necessity bring about the reciprocal delimitations of units. Thought, chaotic by nature, has to become ordered in the process of its decomposition. Neither are thoughts given material form nor are sounds transformed into mental entities; the somewhat mysterious fact is rather that "thought-sound" implies division, and that language works out its units while taking shape between two shapeless masses. Visualize the air in contact with a sheet of water; if the atmospheric pressure changes, the surface of the water will be broken up into a series of divisions, waves; the waves resemble the union or coupling of thought with phonic substance.

The aim of general synchronic linguistics is to set up the fundamental principles of any idiosynchronic system, the constituents of any language-state. Many of the items already explained in Part One belong rather to synchrony; for instance, the general properties of the sign are an integral part of synchrony although they were used to prove the necessity of separating the two linguistics.

As long as the activity of linguists was limited to comparing one language with another, this general utility cannot have been apparent to most of the general public, and indeed the study was so specialised that there was no real reason to suppose it of possible interest to a wider audience. It is only since linguistics has become more aware of its object of study, i.e. perceives the whole extent of it, that it is evident that this science can make a contribution to a range of studies that will be of interest to almost anyone. It is by no means useless, for instance, to those who have to deal with texts. It is useful to the historian, among others, to be able to see the commonest forms of different phenomena, whether phonetic, morphological or other, and how language lives, carries on and changes over time.