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, pol… - Ferdinand de Saussure

The causes of continuity are a priori within the scope of the observer, but the causes of change in time are not. It is better not to attempt giving an exact account at this point, but to restrict discussion to the shifting of relationships in general. Time changes all things; there is no reason why language should escape this universal law.

Psychologically our thought-apart from its expression in words-is only a shapeless and indistinct mass. Philosophers and linguists have always agreed in recognizing that without the help of signs we would be unable to make a clear-cut, consistent distinction between two ideas. Without language, thought is a vague, uncharted nebula. here are no pre-existing ideas, and nothing is distinct before the appearance of language.

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.