The usage of a language is the manner in which the written and spoken language is used, the "points of grammar, syntax, style, and the choice of words", and "the way in which a word or phrase is normally and correctly used". The usage of a language can mean the way people actually use the language, or prescriptively the way one group feels that people ought to use it.
The Chicago Manual of Style says "the great mass of linguistic issues that writers and editors wrestle with don't really concern grammar at all--they concern usage: the collective habits of a language's native speakers", and "the standards of good usage change, however slowly."
Dictionaries are not always accurate guides to "good usage". "Despite occasional usage notes, lexicographers generally disclaim any intent to guide writers and editors on the thorny points of English usage."
According to Jeremy Butterfield, "The first person we know of who made usage refer to language was Daniel Defoe, at the end of the seventeenth century". Defoe proposed the creation of a language society of 36 individuals who would set prescriptive language rules for the approximately six million English speakers.