Several summers ago, I sat on a crowded deck at a party in Washington, D.C., next to my friend Daniela, a spunky, hilarious New Yorker whom I’d met in college. As strangers huddled around us, conversations hummed and collided against the hot night, but I wanted to tell Daniela something only she could hear.

Once, she and I had discussed a shared childhood pastime of speaking gibberish, a secret language, so in order to pass along the secret about a man at the party, I shifted to gibberish—not nonsensical gibberish, but something I suspected Daniela could understand. And she did. For the next few minutes, we inserted this simple phonetic string—/ɪdɪg/—into syllables, transforming our sentences into long-winded, funny sounding staccatos. “Jess” became “Jidigess”; “secret language” became “sidigecridiget lidiganguidigage.” At points we exploded in laughter over what we were doing. I hadn’t spoken gibberish in over a decade, but I surprised myself with my fluency.

“That is the weirdest thing I’ve ever heard,” our friend Guillermo said as he approached us mid-conversation. “You guys really understand each other?”

Of course we did. Long before I’d met Daniela, I had enjoyed speaking gibberish with my girlfriends in the Maryland suburb where I grew up. At the time, we called it simply “idig.” Along with passing notes in class and making up inside jokes, idig was one of the key conduits for telling secrets with my girlfriends throughout elementary and middle school, like the annoying things our parents or teachers did or who had a crush on whom.

The memories rushed back, of gossiping in idig on the phone until my parents got so annoyed they pulled the plug out of the wall, of creating variations of idig at the neighborhood pool, making it even more impossible for boys and teachers to understand. Though most non-idig speakers couldn’t comprehend what we were saying, there was always the chance they might pick up a random name or word.

As an adult, speaking idig with Daniela felt sacred, like a window into the most peculiar and spontaneous part of my youth—a part I hadn’t accessed in so long. As we spoke, I wondered if we were members of something bigger than we realized: a tribe of gibberish speakers, scattered throughout the world.

This tribe has existed in many times and places. As Princeton University comparative literature professor Daniel Heller-Roazen notes in Dark Tongues: The Art of Rogues and Riddlers, “Historians have wished, at different times, to attribute such forms of cryptic speech to as diverse a cast of socially marginal characters as beggars, butchers, fisherman, prostitutes, and prisoners.”

So why do ordinary girls speak in secret languages?

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A few months after the party, I sat on the wood floor of a cozy Brooklyn apartment with sisters Joy and Clarity Haynes, telling stories about gibberish. Joy, an actress and attorney based in Washington, had answered my query on a local listserv. “Our cousin Brady taught us gibberish in the late 70s,” she wrote me immediately, mentioning her older sister, Clarity, an artist in New York. “Your message struck a chord. I’d love to be part in any way.”

After a five-hour bus ride, I arrived to listen to the sisters tell me childhood stories of invented universes, road trips, and “gibberish only” weekends at their cousins’ house, in Austin, Texas. Their older cousin Brady was the ringleader of the neighborhood kids, and days with him were filled with activities.

“He would swing us around in the front yard, play airplane with us, teach us ‘mouth yoga,’ stuff like that,” Clarity remembered. “He was basically the best older cousin in the world.”

In 1979, when Clarity was eight, and Joy was six, Brady introduced them to gibberish.

“There was this tiny little room, a dark study, with books on the wall and a leather chair, and it always felt mysterious and dark in there,” Joy said. “It felt like ‘wow, we’re in this secret place learning a secret language and we’re going to be able to talk and nobody’s going to understand us.’”

Soon after, the sisters moved from Texas to Washington, D.C. And for the rest of their childhood, they passed the hours on family road trips speaking gibberish. It was a way to get back at their parents, who would often revert to Portuguese when they didn’t want the kids to understand. In the back of the station wagon, gibberish opened the door to a secret world.

In the late 1980s, Brady, who came out as gay in his teens, became terminally ill with AIDS. Now, decades after his death, gibberish is a way the sisters still remember and honor their cousin.

As I talked to Clarity and Joy, I felt an undeniable kinship. Communicating in our shared language was the backbone of our new connection.

“Speaking to you in gibberish … I almost feel like you must be part of my family,” Joy told me. “Me too,” Clarity agreed: “It’s kind of surreal—like, are we related?”

[All speaking in gibberish]: Joy: “Definitely. It is so weird to hear you speaking gibberish. It makes me feel like you must be someone from my family.” Clarity: “Yeah, me too. It’s like, the first time we have ever really met anybody else who speaks it, and it’s kind of surreal.” Jess: “It is so much fun.” Clarity: ”Yeah, it really is.” Joy: “It would be fun… more fun… to do it in public than alone in your house.” Jess: “True.” Joy: “Just go to a restaurant or a store and act like it is the most normal thing ever…” C: “Although I think we’ve done that before.” Joy: “Not as adults” C: “No, that’s true; maybe young adults.” Joy: “Maybe yeah.” Clarity: “I think we have. Yeah.”

Though there appears to be no definitive research on gender and gibberish, it became clear to me that girls are drawn to gibberish and the dozens of other secret languages and language games, also called argots and ludlings, because using them builds social bonds. Though girls aren’t threatened in the same way as others who use secret languages, like prostitutes or criminals, using gibberish creates a sense of exclusivity and power for girls at a time when they are otherwise inherently powerless. Though boys like secret codes too, it seems as if more girls use gibberish and remember it fondly.

On a quest to find gibberish speakers, I met 71-year-old Susan Fertig, who learned “LF” language from her mom at age seven (stick the sounds /lf/ after a vowel in each syllable and repeat the vowel, so that “Bobby was a boy” becomes “Bolfobblfy walfas alfa bolfoy”). The language was known as a secret among the women in the family, and Fertig grew up using it with her younger sister at their small American school in the Philippines.

Susan [speaking in normal English]: This is one of my favorite books when I was a little girl. It's called Toby's Trip, and it's about a dog that gets in a picnic basket and gets taken on to the train when the little girl and the little boy that have him go for a trip. So, [beginning to speak in LF language]: Bobby was a little boy who liked to ride on trains. His sister Betsy liked to ride on trains, too. Toby didn’t know whether he liked to ride or not, because he was – laughs – very young and had never been away from home. “Baggage car,” said the [stumbling] conductor. Jessica [speaking normal English]: “Conductor is hard to say. How do you say conductor?” Susan: "Colfondulfuctolfor." Jessica [stumbling]: "Colfondulfuctolfor." Susan: "Right."

In middle school in Oregon, Kelly Chastain, now in her 40s, spoke “oppish” (add an /ɔp/ before each vowel sound in an English word, so “language” became “lopangopage”) with her best friend Jenna, as a way to drive Jenna’s brother crazy.

And in Queens, New York, a 13-year-old Elena Hecht, now 28, locked herself in the bathroom with her seven-year-old sister, Ava, declaring: “We can't leave the bathroom until you can speak Ubbi Dubbi fast enough so that mom and dad won't be able to understand us.” (To speak Ubbi Dubbi, you add /əb/ before each vowel in a word, so “hello” becomes “hubellubo”).

In a scene from the 1998 movie “Slums of Beverly Hills,” cousins Rita (played by Marisa Tomei) and Vivian (played by Natasha Lyonne) see each other for the first time in years. It’s clear they’ve outgrown their girlhood innocence, as they’re both now preoccupied by men, and as they interact, there’s a palpable tension. To reestablish connection, Rita, the older of the two, smirks and unleashes a stream of gibberish—which appears subtitled on the screen. “So…” she says, “citigan yidigou stidigill spidigeak idigour sidigecridiget lidiganguidigage?”

Immediately, Vivian softens, the tension dissipates, and the young women continue gossiping.

To sociolinguist Deborah Tannen, the use of gibberish by girls makes perfect sense. “I think often, when we sense we’re talking to someone who shares our background or identity in some way, we like to switch into a language that they will recognize because it’s a way of acknowledging and building on that bond,” she said. “And girls and women not only spend more time talking, but they create connections through what they’re talking about.”

Tannen, a professor of linguistics at Georgetown University, began her career studying differences in conversational styles due to factors like age and ethnic background. But in the 1980s, she became interested in the work of anthropologist Marjorie Harness Goodwin, who explored differences in the complex social worlds of boys and girls. According to Goodwin’s research, girls typically sit and talk with their best friends, often telling secrets. For boys, activities are at the heart of what connects them; best friends are the ones they go out and do things with.

That’s what led Tannen to begin to focus on the way gender changes how people use language. In 1990, she published the bestselling You Just Don't Understand: Women and Men in Conversation, which argues that girls and women use language largely as a way of negotiating relationships.

“For girls and women, their connections with each other are the center of their lives,” Tannen told me. “And talk is the glue that holds those relationships together. The fact that you can share a private language, create that connection, feel you’re part of that group and that you’re an in-member of the group is going to carry so much weight that it’s going to be really, really attractive to girls,” she said.

It helps that gibberish forms are relatively simple to create. As Daniel Heller-Roazen writes, “Secret languages do nothing but recapitulate the various units that are operative in a grammar, from the phoneme to the syllable, the word to the phrase and the complete sentence.” Bert Vaux, a linguistics professor at Cambridge University and an expert on language games, argues that syllabic games have relatively few variations in their structure. You can move the first syllable to the end, move the final syllable to the beginning, transpose the first and second syllables, transpose the final and penultimate syllables, or invert the order of all the syllables. Some language games allow for a virtually limitless set of transformations. In the Norwegian ludling Smoi, for example, a word’s syllables are rearranged and spoken in any order, as long as they can be pronounced.

As it turns out, language games like gibberish can be found in languages around the world. Pakistan has fay ki boli and Cambodia has pheasa krolors. Across the Spanish-speaking world, jerigonza is a common way to transform words, by adding /p/ after each vowel in a word, and then repeating the vowel. Thirty-three-year old Negar Mortazavi, a native Persian speaker from Tehran, Iran, is the third generation of women in her family who speak zargari, which involves adding a /z/ after every vowel, and then repeating the vowel. According to the International Encyclopedia of Linguistics, zargari began as a secret language used by goldsmiths known as zargars in Persian. Now, Mortazavi says, zargari’s use is so widespread that it’s no longer a secret. Her 90-year-old grandmother, Eshrat, still has fond memories of speaking zargari with friends in elementary school.

In some places, women use secret languages to keep themselves safe. In the 1980s, Teshomme Demisse and Lionel Bender described an argot used by “freelance prostitutes” in Addis Ababa in order to keep secrets such as “concealing conversations and planning tricks at the customers’ expense” and holding themselves apart from the “ordinary run of bar prostitutes.” Daniel Heller-Roazen describes javanais, apparently used by 19th century prostitutes “for protection from male clients.” Were they making use of secret languages from an earlier time in their lives?

Ten years ago, Meredith Doran, an assistant professor of French and Applied Linguistics at Pennsylvania State University spent a year with French youth and teenagers in minority communities on the outskirts of Paris, studying their use of verlan, a popular syllable-swapping French language game used mostly among minority youth. She found that verlan was used to negotiate a “we” within a community that was otherwise fractured among ethnic lines.

“Language is one of the cheapest tools available to kids,” she says. “You don’t have money or power, but you’ve got words. There’s a thrill and a power to that.”

The popularity of gibberish among girls makes sense if you consider that women tend to be at the forefront of many linguistic changes. Girls who speak gibberish now may be the linguistic innovators of the future. Research has shown that women largely lead changes, such as the use of like to introduce reported speech or thought, as in: “And then he was like, ‘I like you,’ and she was like, ‘I like you, too’.” According to a 2009 study by Sali Tagliamonte, a professor in the Department of Linguistics at the University of Toronto, and Alexandra D’Arcy, an associate professor of Linguistics at the University of Victoria, men are generally a generation behind when it comes to adopting certain language innovations.

“One of the predominant ways we mark allegiance and alignment is through language,” says Tagliamonte. She grew up speaking Pig Latin in Quebec with her best friend until it made their teachers so angry, they forced the girls to stop. “Secret languages are the epitome of wanting to be part of a group and excluding other people from that group,” she says.

[All speaking in gibberish]: Jessica: "And what kind of group would you guys say your friends are?" Emily: "Funny." Ariana: "Um, kind of random. Like not super popular, but moderate." Jessica: "Do the popular girls speak gibberish?" Ariana: "They're not cool enough."

I’m not sure exactly when I stopped speaking gibberish with my friends, but I imagine it was around age 13, when I began to explore other sources of power. I started studying Spanish—a language I now use in my everyday life as a resident of Bogotá, Colombia. And boys and grades seemed to offer more powerful rewards than girl clubs and secrets.

Still, it has been important to pass down gibberish to other girls. During a short stint working in an elementary school, I taught the rules of gibberish to a few 4th grade students. Similarly, Clarity and Joy passed the language on to their younger stepsister and to other cousins. Susan Fertig, too, taught “LF” to her grandchildren.

Each of us felt a responsibility to arm a new generation of girls with the power of this secret language, right at the time when they could benefit most from using it. If you want to empower girls, teach them the secret language you used to speak. I think back to those years, before I was aware of my own force as a woman, and when my thoughts and opinions were real but dismissed because I was “just a girl.”

With my friends, communicating in idig as fast as we could, we felt powerful and connected. Gibberish was exclusively ours—a secret from those who held authority over us, like our parents and teachers. And as a bonus, it was easy, pure fun.

Play and expression, bonding and friendship—those were the gibberish days.

It will always be my little secret.