On South Goulburn Island, a small, forested isle off Australia’s northern coast, a settlement called Warruwi Community consists of some 500 people who speak among themselves around nine different languages. This is one of the last places in Australia—and probably the world—where so many indigenous languages exist together. There’s the Mawng language, but also one called Bininj Kunwok and another called Yolngu-Matha, and Burarra, Ndjébbana and Na-kara, Kunbarlang, Iwaidja, Torres Strait Creole, and English.

None of these languages, except English, is spoken by more than a few thousand people. Several, such as Ndjébbana and Mawng, are spoken by groups numbering in the hundreds. For all these individuals to understand one another, one might expect South Goulburn to be an island of polyglots, or a place where residents have hashed out a pidgin to share, like a sort of linguistic stone soup. Rather, they just talk to one another in their own language or languages, which they can do because everyone else understands some or all of the languages but doesn’t speak them.

This arrangement, which linguists call “receptive multilingualism,” shows up all around the world. In some places, it’s accidental. Many English-speaking Anglos who live in U.S. border states, for instance, can read and comprehend quite a bit of Spanish from being exposed to it. And countless immigrant children learn to speak the language of their host country while retaining the ability to understand their parents’ languages. In other places, receptive multilingualism is a work-around for temporary situations. But at Warruwi Community, it plays a special role.

Ruth Singer, a linguist at the Wellsprings of Linguistic Diversity Project of the Australian National University, realized this by chance, and wrote about receptive multilingualism at Warruwi Community recently in the journal Language and Communication. In 2006, for one of her trips for fieldwork on South Goulburn, Singer and her husband had a Toyota truck shipped from Darwin by boat. Though the island’s not very big, there aren’t many cars, so having one is a social lubricant. Singer and her husband became friends with a local married couple, Nancy Ngalmindjalmag and Richard Dhangalangal, who had a boat and trailer but no car, and the two couples ended up going fishing and hunting, and digging up turtle eggs on the beach. That’s when Singer noticed that Nancy always spoke to Richard in Mawng, but Richard always replied in Yolngu-Matha, even though Nancy also spoke fluent Yolngu-Matha.

“Once I started to work on multilingualism and tuned my ear into how people were using different languages,” Singer wrote in an email, “I began to hear receptive-multilingualism conversations all over Warruwi, like between two men working on fixing a fence, or between two people at the shop.”

There are a variety of explanations for this, Singer says. In the case of her married friends, Richard didn’t speak Mawng, because he wasn’t originally from Warruwi Community. If he did so, it might be perceived as a challenge to rules that exclude outsiders from claiming certain rights. Also, Yolngu-Matha has more speakers, and those speakers tend to be less multilingual than speakers of smaller languages.

Read more: The Atlantic