There's a fantastic language phenomenon in France called "Verlan" that's certain to have sent many French learners scrambling for dictionaries over the years.
The slang language essentially sees the sounds of a word's syllables pronounced back-to-front. In fact, the word "verlan" itself is an example of Verlan, as it's the French word "L'envers" (reverse) in reverse.
The phenomenon, which some suggest took off after World World Two, is incredibly popular with younger people.
But it doesn't just work on any old word - it's something that has to be learned from a select few examples.
Although originally most words were linked with sex or drugs in order to keep them secret, the number of Verlan words has boomed in recent years.
For example, the word bizarre turns into "zarbi" (yes, it's spelled differently too), the word for woman (femme) becomes "meuf" and the word for crazy (fou) becomes "ouf".
And did you know that the name of the most popular French-language singer right now - Stromae - is a Verlan form of the word maestro? The language is hugely popular in music, especially French rap, where the sounds of the words are often just as important as the meaning.
Belgian performer Stromae. Photo: AFP
If you've never heard of Verlan before, you'd be forgiven for thinking it was some kind of underground code, but the examples above are such mainstays in the French language that most French people under the age of 40 wouldn't even think twice about using them.
Other common examples are "chelou" for "louche" (to mean a strange, bizarre or shady), "laisse béton" for "laisse tomber" (or "let it go"), and "chanmé" meaning great, wicked or cool, which is taken from "méchant", which means bad, or wicked.
French language expert Camille Chevalier-Karfis, who runs the language learning website French Today, says that Verlan is known for making occasional comebacks, the last major one of which was around 10 to 15 years ago.
"Each time it makes a comeback, some 'newer' slang expressions stick in everybody's vocabulary, when other words are only 'in' for a couple of years and then become stupid very fast," she told The Local.
She pointed out that "laisse béton" - which is also the name of a hit French song from the seventies - is no longer considered to be a "fashionable" phrase, rather it's just a part of the French vocabulary.
But it's not always simple. The last time Verlan did the rounds, she said, it became so over-prevalent that it could be tricky to keep up.
For example, she said, a sentence like "Dammit, my jacket was stolen in the subway!" - which should be "Fait chier, on m'a fauché mon blouson dans le métro!" - suddenly became "Fait ièche - on m'a fécho mon zomblou dans l'tromé!"
The Paris Métro... or the Tromé de Ripa? Photo: Simon/Flickr
While examples like this are (thankfully) relegated to the past, the spike in Verlan brought about a bunch of words that became part of everyday slang, such as "portnawoiq" (slang for "n'importe quoi" - nonsense), "teuf" for "fête" (party), "t'es relou" (for "lourd" - you're a pain).
Opinion on Verlan is divided, especially among language learners. While some may complain about this "child-like code language", others like French language expert Laura K. Lawless count themselves among the fans.
"I think Verlan is great, it's a way of playing with the language that is so simple, and yet produces a word that is so different that it's incomprehensible at first sound," the Francophile, who created LawlessFrench.com, told The Local.
She suggested that Verlan looked likely to hang around too, not least because some words become so mainstream that they get "switched" for a second time
For example, she pointed out that femme (woman) first changed to "meuf", then became so common that it got "re-Verlaned" to become "feumeu". The word for Arab (arabe) saw a similar journey, initially switching to the now hugely popular word "beur" before more recently being re-dubbed to "rebeu".
Une femme... or should that be a meuf? Photo: Daniel X. O'Neil/Flickr
While the words that have entered common parlance seem here for good, the language isn't developing much (with the exceptions of a few re-Verlaned words). Perhaps it's because all the best words have been created already, coupled with the fact that the language is seen more as something to learn than to invent.
In fact, both the language experts agreed that Verlan wasn't influencing today's slang to the same extent as it did in the past. Nowadays, youths are preferring to use text speak, English words, and even Arabic-influenced words when they want to use slang.
But don't think this means you shouldn't learn the basics if you want to understand the French.
After all, every single French person under the age of 40 who The Local spoke to for this story agreed that Verlan was an integral part of everyday French life.
So with this in mind, we advise you to memorize the examples above, if for no other reason that to impress your French friends.
Enjoy. Or should that be joyen?