Somewhere around 1900, in a Buenos Aires tenement, somebody asked for a feca instead of a café.

In a Paris suburb decades later, somebody described a woman as a meuf instead of a femme.

In Lambrate, a working district of Milan, in the 1970s, somebody went home to the saca instead of the casa.

None of them had heard of the others. All three had the same problem: they needed to say something out loud in front of people who should not be able to follow it.

The solutions they invented are almost identical. That is the interesting part.

The trick, in one line

Take a word. Break it at the syllable. Put the pieces back in the wrong order. What comes out sounds like nothing, unless you know the rule.

It is the linguistic equivalent of turning your back and whispering, and every language that has been policed hard enough has invented some version of it.

1. Verlan: French, and the one that escaped

Verlan is l'envers ("the reverse") run through its own machine. It started as street code and ended up in advertising copy.

ouf: crazy, from fou reversed. C'est un truc de ouf, it's a crazy thing.

meuf: woman or girlfriend, from femme. Completely ordinary in spoken French now.

relou: annoying, a pain, from lourd. Nothing to do with weight.

vénère: furious, from énervé. Pourquoi tu es vénère?

chelou: shady, sketchy, off, from louche.

cimer: thanks, from merci. If it sounds like a sneeze, this is why.

Then something revealing happened. Verlan worked so well that everyone learned it, which defeated the point, so speakers ran words through a second time. Arabe became beur, and once beur was common knowledge it became rebeu. When the code is cracked, you re-encode. The full verlan guide is here, and the wider street vocabulary is in French argot.

2. Vesre: the same idea, in Buenos Aires

Vesre is revés ("backwards") turned backwards. It belongs to Rioplatense Spanish and it is almost purely spoken, which is why it is so badly served by dictionaries.

feca: coffee, from café.

jermu: woman or wife, from mujer.

gomía: friend, from amigo.

tordo: doctor, from doctor.

broli: book, from libro.

lope: hair, from pelo.

nerca: meat, from carne.

It is still productive today, which is how you get zapi for pizza. Tango lyrics are stuffed with it, which is the main reason a century-old street code is still legible to Argentines who have never used it themselves.

3. Lunfardo: the vocabulary underneath

Vesre is a mechanism. Lunfardo is the word list it operates on, and it is the larger story.

Late nineteenth-century Buenos Aires was being remade by Italian immigration, and the slang of the port and the prison absorbed it wholesale:

laburar: to work, from the Italian lavorare. The everyday verb, not a jokey one.

fiaca: laziness, the specific feeling of not wanting to move, from the Italian fiacca.

morfar: to eat, and to eat properly rather than to nibble.

guita: money, cash.

pibe: kid, lad. Pibe de oro is what Argentina called Maradona.

mina: woman, informal and very common.

bondi: bus.

quilombo: a total mess, a shambles. Politically as well as domestically.

Argentines use these hourly. Very few of them file the words under "slang" any more, which is what successful street vocabulary looks like at the end of its life.

4. Riocontra: Milan invents it again

Riocontra is contrario through the same treatment. It grew up in the Lambrate district of Milan in the 1970s, reached a wider audience through the 1983 film Il ras del quartiere, and then spread across the whole country on the back of Italian trap and rap.

saca: house or home, from casa.

nobambi: kid, from bambino.

tocapi: understood, got it, from capito.

torfu: theft, from furto.

termo: death, from morte.

If you have listened to Lazza and wondered why a perfectly ordinary Italian word arrived inside out, this is why.

5. Cockney rhyming slang: the two-step

English does not flip syllables. It does something arguably worse.

Step one: replace the word with a phrase that rhymes with it. Step two, and this is the step that makes it impenetrable, delete the rhyming part.

dog and bone: phone. Clipped in use: he's on the dog.

plates of meat: feet.

trouble and strife: wife.

apples and pears: stairs.

porkies: lies, clipped from porky pies. He's telling porkies.

Barnet: hair, clipped from Barnet Fair. Nice Barnet.

butcher's: a look, clipped from butcher's hook. Have a butcher's at this.

By the time the rhyme is gone, there is no thread left to pull. Barnet and hair have nothing in common at all.

6. Rotwelsch: the German one you already speak

Germany took the other road. Rather than rearranging German, Rotwelsch imported from Yiddish, Hebrew, Romani, Latin and Czech, so that the sentence stayed German-shaped while the important words became unreadable.

It was the cant of travellers, pedlars, beggars and thieves. Martin Luther named it in the sixteenth century. Nineteenth-century police forces compiled dictionaries of it, which is a good measure of how well it worked.

It is extinct as a language, and it is sitting in your mouth anyway:

Bock haben: to be up for something. Ich hab keinen Bock is the most-used sentence in Germany.

berappen: to cough up, to pay out reluctantly.

aufmucken: to kick back, to protest against someone above you.

baldowern: to case a place, to scope something out. Still alive in Berlin speech.

Bau: prison. Im Bau sitzen, to be inside.

Every German alive says ich hab keinen Bock several times a week. Almost none of them know they are quoting a thieves' cant.

The three things that are always true

Look at the five together and the same pattern comes up every time.

They were invented against authority. Ports, prisons, immigrant districts, the road. Never universities.

They escaped through music. Tango carried vesre. Rap carried verlan and riocontra. Hamburg hip-hop did the same job for northern German. Music is how a private code becomes a public one.

Success kills them, so they mutate. Verlan grew a second layer once the first was decoded. Rhyming slang clips itself. A code that everybody understands has to move or die.

Why any of this matters if you are learning

Because a dictionary is exactly the wrong tool.

A dictionary is a record of meanings people have agreed on. This vocabulary exists specifically so that no such agreement leaks out. Type meuf or feca into an older translator and you will get nothing, or worse, a confident answer about a different word.

And you cannot route around it. This is not decoration on the edge of the language. It is a good part of what you will hear in a bar, in a lyric, in a film, and from anyone under forty. Sounding almost native is mostly a matter of understanding the half of the language that never got written down.

Catching it with Vokabulo

Feed it the sentence, not the word. When a word arrives inside out, you usually cannot tell where it starts and ends. Paste the whole line into Vokabulo's Translate rather than the fragment you think you heard. Context is what lets the AI work out that chelou is doing the job of louche.

Save the scene, not the gloss. Relou = annoying will not stick, because it is a fact with nothing attached. The friend who would not stop talking about his crypto portfolio, filed under relou, will. That is what Scenes are for, and a free account gets three of them to try the idea out.

Then let it come back. Slang decays out of your memory faster than textbook vocabulary because you meet it less often. Spaced repetition through the levels is what turns I have seen that word into I can use that word, which is the passive to active gap in one move.

The short version

Every language you are learning has a layer built by people who did not want to be understood, and every one of those layers eventually leaked into ordinary speech.

You are not being taught it, because it was never designed to be teachable. You will hear it on day one anyway.

Heard something that sounded like a word played backwards? Drop the whole sentence into Vokabulo and find out what it was. Free to start on iPhone and iPad. 🔤