British slang is English language slang used and originating in Great Britain and also used to a limited extent in Anglophone countries such as Ireland , South Africa , Australia , Canada , and New Zealand , especially by British expatriates. It is also used in the United States to a limited extent. Slang is informal language sometimes peculiar to a particular social class or group and its use in Britain dates back to before the 15th century. The language of slang, in common with the English language, is changing all the time; new words and phrases are being added and some are used so frequently by so many, they almost become mainstream. While some slang words and phrases are used throughout Britain e.