'Ain't' isn't a word either

What actually happened

The 1961 controversy is one of the great fights in the history of dictionaries. Webster's Third, edited by Philip Gove, took a descriptive line and declined to append moral judgement to usage. The reaction was ferocious: the New York Times called it a scandal, Life ran an editorial, and the Chicago Tribune announced it would keep using the previous edition. Rex Stout wrote a Nero Wolfe novel in which Wolfe burns a copy page by page. Its treatment of 'ain't' was the flashpoint.

The word's history undercuts the snobbery. It descends from 'amn't', a natural contraction of 'am not', and 'an't' was unremarkable in the speech and writing of eighteenth-century English gentry, appearing in Swift and Fielding and Congreve. It got stigmatized in the nineteenth century, largely by class-conscious prescriptivists, and became a marker of Cockney and rural speech rather than of aristocratic ease.

The practical residue is that English has an actual hole where 'amn't' should be. "I am going, aren't I?" is what standard English forces you to say, which is grammatically incoherent if you unpack it: nobody says "I are not going." 'Ain't' filled that gap cleanly and was driven out. The advice to avoid it in formal writing stands. The claim that it is not a word does not, and hasn't since at least 1961.