Speech has both an individual and a social side, and we cannot conceive of one without the other. - Ferdinand de Saussure

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.

The scope of linguistics should be:

Writing obscures language ; it is not a guise for language but a disguise.