THIRTEEN languages in Germany are on UNESCO's endangered list. Kiezdeutsch, the argot of inner-city teenagers, is not one. “Morgen ich geh Kino,” meaning “Tomorrow I'm going to the cinema,” a young Kreuzberger may say. In standard German that would be “Morgen gehe ich ins Kino”, with the verb restored to second place and a missing “to the” added. Words borrowed from Turkish (lan, meaning dude) and Arabic (yalla!, or come on!) might also intrude.

You will hear such language in Berlin and other big cities. Most Germans assume that the speakers are immigrants or their children. Not necessarily, says Heike Wiese, a linguist at the University of Potsdam who has written a new book on the topic. “All types of kids in multilingual areas,” including those with German roots, speak Kiezdeutsch. There are foreign analogues: straattaal (street language) in the Netherlands; Rinkeby-svenska, named for a multi-ethnic Stockholm neighbourhood in Sweden.

Kiezdeutsch is a new dialect, Ms Wiese says, noticed by scholars in the 1990s but perhaps a decade or more older. It has its own grammatical rules, which can allow for greater expressiveness than standard German. By shoving the verb over, Kiezdeutsch can emphasise not just who is doing something but when. “Musstu” is a pungent fusion of “you” and “must”. Linguists are used to mourning the death of dialects; now they can watch one grow “in real time”, Ms Wiese says.

Such opinions can make people angry, in some cases enough to send Ms Wiese obscene e-mails. At least a third of children with non-German roots and a tenth of those growing up in German-speaking homes do not speak standard German properly. Unless they learn they will be hard to employ and may end up on the dole. To babble in Kiezdeutsch instead of proper Hochdeutsch can suggest acceptance of a parasitical future.

Kiezdeutsch is not a dialect but a style of speaking, says Helmut Glück, professor of German at the University of Bamberg. Such patois often develops among students, soldiers and other groups to foster a sense of belonging. Purists complain of its shrunken grammar and vocabulary. Yet Kiezdeutsch is not “broken German”, insists Ms Wiese, though she thinks teenagers should speak the standard language, too. It encourages mixing of people of different origins, not exclusion. Some Kiezdeutsch-speakers even embrace the stigma. The lingo got buzz from “Kanak Sprak”, a book published in 1995 (Kanake is an insulting word for certain foreigners). Comedy amplified it. Now you hear echoes among teenagers who never set foot in Kreuzberg. Kiezdeutsch is here to stay, lan.