Slangis the use of informal words and expressions that 1 standard in the speaker's dialect or language. It is often used to identify with one's peers and, although it 2 be common among young people, it is used by people of all ages and social groups. Slang is informal language sometimes peculiar to a particular social class or group and its use in Britain dates back to before the 16th century. The language of slang, in common with the English language, 3all the time; new words and phrases 4. The nations of the United Kingdom all have their own slang words, as does London. British slang has been the subject of many books including a seven volume dictionary, published in 1889.