The distinction between literary language and colloquial speech is, of course, not identical with that between primary spoken form and secondary written form, as our use of ‘written’ and ‘spoken’ style may have suggested: contractions like 'don’t', 'can’t', 'ain’t' belong to various levels of ‘spoken’style; still, they have a written form, and many words that are hardly used outside of written texts have a pronunciation of their own, if only because they may have to be read aloud.
- Martinet (1962), Pag. 124