“Argentinian Spanish is sort of hard to understand,” said my sister as she plugged in a fan. It was hot and still in Buenos Aires and we were drinking lemonade on her balcony.

I’d just flown into South America for the first time, and I hadn’t slept much on the plane. I was more concerned about my overpowering jet lag than mastering the local dialect. But fresh off a lengthy stay in Nicaragua, I spoke enough Spanish to get by… or so I thought.

Later that evening, my sister took me to meet her new boyfriend. Fermin, a native porteño (Buenos Aires local). He and his friends were charismatic and kind, but I could barely understand a word they said. They were speaking Spanish, but their vocabulary was filled with words I’d never heard before.

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Throughout the evening, Fermin repeatedly referred to his friends as ‘los pibes’, meaning ‘the boys’ or ‘the kids’ in lunfardo, a form of popular slang in Buenos Aires. It’s one of approximately 6,000 words that make up the lunfardo lexicon. Over the course of that evening with Fermin and his pibes, I heard them use mango (rather than dinero) when discussing money and morfi (not comida) to talk about food.

The name ‘lunfardo’ hints at the history behind the slang. In the late 19th Century, Argentinian police officers noticed that thieves and other small-time criminals were using a new range of words to communicate with each other. Assuming that the slang was a sort of criminal jargon, the law enforcement officials started making lists of the words and phrases they heard. They called the lexicon ‘lunfardo’, meaning ‘thief’ in Spanish.

But according to Oscar Conde, an Argentinian professor who’s written two books on the subject, the cops were wrong.

“The birth of lunfardo is not related with criminality,” Conde writes, “but with European immigration to Argentina between 1880 and the beginning of World War I.” During those years, four million people, mostly Italians and Spaniards, arrived in Buenos Aires. The city became, as Conde puts it, “a real-life Babel”.

The city became a real-life Babel

In Buenos Aires at the turn of the 20th Century, Italian words were quickly adopted into everyday speech, sometimes with slight modifications. The Italian word femmina (woman), for instance, was shortened to mina; fiacco (laziness) became fiaca. Similarly, bacán (of or relating to the good life), biaba (hair dye or perfume) and laburar (to work) all have a basis in Italian.

José Gobello, 20th-Century Argentinian writer and founder of the Academia Porteña del Lunfardo, a non-profit institution dedicated to the study of colloquial speech in Argentina, suggested that pibe (Fermin’s nickname for his friends) comes from the Italian word pivello, meaning ‘youngster’ or ‘novice’, or perhaps from pive, a word in the Genoese dialect that means ‘apprentice’.

Spanish wordplay – particularly vesre, a form of language modification in which the last syllable of a word is moved to the start – also contributed to the development of lunfardo. The word ‘vesre’ itself is a play on the Spanish word revés, meaning reverse. Amigo (friend) became gomía, café (coffee) became feca and leche (milk) became chele.

Lunfardo spread through everyday conversation, and it wasn’t long before the slang started appearing in literature, journalism and even theatre. But it was the birth of the tango-canción (tango song) that cemented lunfardo’s role in Argentinian culture.

On 3 January 1917 in Buenos Aires’ Teatro Esmeralda, French-Argentinian singer-songwriter Carlos Gardel – who’d go on to become the greatest legend in the history of tango – performed the song Mi Noche Triste. Unlike most tango music, which was more freeform in composition, this had a defined beginning, middle and end. Like a pop song, Mi Noche Triste had widespread appeal and was often played on the radio. And the lyrics were filled with lunfardo.

Tango was the soundtrack of Buenos Aires, and lunfardo was at the heart of it. “There was a very productive association between the two,” Conde says. “Tango lyrics contributed to the diffusion of the language; in turn, lunfardo gave tango a tone and a style.”

They’re still inextricable today.

Tango was the soundtrack of Buenos Aires, and lunfardo was at the heart of it

It's now been 10 years since I first set foot in Argentina to visit my sister. During the past decade, I’ve lived on and off in Buenos Aires, in and out of different jobs and relationships that have taken me back and forth between South America and my native US. I speak Spanish pretty well now, but porteño slang can still prove baffling. Lunfardo is so deeply ingrained in Argentinian culture that I sometimes don’t even know I’m hearing it – or speaking it. Part of language acquisition, after all, is mimicry.

“Qué quilombo,” I said to a Buenos Aires taxi driver one evening. We’d been stuck at the same traffic-clogged intersection for almost 10 minutes, and I was running late for my boyfriend Eduardo’s basketball game. The taxi driver laughed and asked me where I’d learned that expression. I was just repeating a phrase I’d heard other people say in similar situations. Later, I looked it up: originally referring to a brothel or a hideout for slaves, quilombo has been repurposed by lunfardo speakers to describe a mess or a disorganised situation.

After the game, Eduardo and I spent the evening in the tango club next door to the basketball court. There was no orchestra that night, just an antique sound system playing old Gardel classics while men and women in close embrace moved across the wooden dance floor. I’ve studied the dance and I’ve tried to understand the song lyrics: both are challenging.

“Don't worry, I don’t understand all the words either,” Eduardo said. “And I grew up listening to tango all the time with my dad.”

As another song began to play – Por Una Cabeza, a classic tango that Gardel wrote and recorded in 1935, the same year he died in a tragic plane crash – Eduardo’s phone beeped. He picked it up and laughed at the incoming text message.

“A que hora abre el cheboli?” (“What time does the club open?”) read the incoming message. His friends were apparently making plans for the weekend.

I suddenly understood what made him laugh. In the middle of our conversation about tango lyrics, porteño wordplay and the evolution of lunfardo, the text message exemplified all three. Cheboli is vesre of boliche, a Spanish word used in rural Argentina to refer to a small general store; it has been adapted in lunfardo to mean ‘tango club’.

It has been 100 years since Gardel invented the iconic tango song that helped weave lunfardo into everyday conversation. But in Buenos Aires, the playfulness in language and the joy in music are very much alive and well.

Lost in Translation is a BBC Travel series exploring encounters with languages and how they are reflected in a place, people and culture.

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