London (AFP) - Sitting on the floor of a rehearsal room in east London in leggings, T-shirts and headbands, a group of teenage dancers laughed about how quickly their language changes, rattling off "old" words still unfamiliar to many older English speakers.
"Safe" meaning good, "boomting" or "chungting" meaning good-looking, and "a lie!" as an exclamation of agreement were all deemed to have "died down".
"That was before. What else was there? Moist?" asked 19-year-old Tafote Akerejola.
"No I never used that one! That one annoyed me!" said Adanna Lawrence, 16, explaining that "Moist meant you're dry. Like you're dead up, you're nothing."
"Then that moved on to wet," added Akerejola. "But I wouldn't say someone who is boring is moist or wet cos I have my own slang. You personalise it as well."
The language used by the members of the East London Youth Dance Company, whose ages range from 14 to 19, is an example of what has been termed "Multicultural London English" (MLE) by academics -- a way of speaking born from the melting pot of immigrant communities in the capital and spreading rapidly throughout Britain.
Though it emerged only in the last three decades, among young people the dialect has largely replaced the traditional London Cockney famed for its rhyming slang.
It includes elements from sources as varied as the Caribbean, West Africa, Britain's grime hiphop movement and the ex-colonial English of Pakistan.
Words are often used to mean the opposite of their traditional meaning, with "sick", "bad" and "wicked" all meaning good, according to the teenagers.
To address friends they say "fam", a short version of "family", and pepper their sentences with "like", drawing out the vowel to sound like an "a".
MLE is distinct to other urban dialects around the world because it is impossible to know the ethnic background of speakers by their accents alone, according to academics.
"The speakers of MLE are governed not by class or by race or by colour, but by age," said slang expert Jonathon Green.
"People between about 15 and 30. They could be white, they could be black, they could be brown."
- 'Everyone mixing together' -
Experts say that the London lingo could indicate the way that other languages will evolve in the future.
Linguists use the term "multiethnolects" to describe such tongues, which have also begun to emerge in other European countries like France and the Netherlands.
MLE's dominance among all kinds of young Londoners may be due to mixed communities, an emphasis on multiculturalism over integration, and an attitude that English is elastic, according to Birkbeck, University of London professor Penelope Gardner-Chloros, who led a study comparing MLE to its counterpart "Multicultural Paris French".
"In France there is a much bigger divide between second and third generation migrants and what you might call the 'long-term indigenous', and this is reflected in the language," Gardner-Chloros said.
In contrast to France, where the French Academy decides the language's official vocabulary and rules, Britain's attitude to English is much more flexible.
"English is a notoriously malleable, open, changable, variable, even welcoming language. It always has been," said Green.
MLE has attracted some negative reporting in the British press, where it was dubbed "Jafaican" or fake-Jamaican when it was first noticed. It has also been seized on by right-wing groups as an example of the dangers of immigration.
It didn't help when young Londoner Mohammed Emwazi or "Jihadi John" appeared in Islamic State group beheading videos, delivering threats to Britain and the United States in a distinct MLE accent.
But some have turned the language to their advantage, even building careers from it like rapper Dizzee Rascal, who began his release "Pagans" with the line: "I don't speak queen's English but I'm still distinguished".
Akerejola, the dancer, said she was proud of the language she said made her feel "we have our own thing, we're a family".
"There are some slang words that come from Jamaica, some from Nigeria. It's everyone mixing together," Akerejola said.
"We adapt. It's flavourful," she added. "It's a good thing."