The small town of Kuşköy, which is tucked into an isolated valley on the rainy, mountainous Black Sea coast of Turkey, looks much like the other villages in the region. Houses balance on steep hillsides beside tea fields and hazelnut orchards. A narrow white minaret and a small domed mosque stand beside a noisy creek. Kuşköy is remarkable not for how it looks but for how it sounds: here, the roar of the water and the daily calls to prayer are often accompanied by loud, lilting whistles—the distinctive tones of the local language. Over the past half-century, linguists and reporters curious about what locals call ku__ş dili, or “bird language,” have occasionally struggled up the footpaths and dirt roads that lead to Kuşköy. So its thousand or so residents were not all that surprised when, a few years ago, a Turkish-born German biopsychologist named Onur Güntürkün showed up and asked them to participate in a study.

Photograph courtesy Onur Güntürkün

Whistled languages, although unusual, have been around for centuries. Herodotus described communities in Ethiopia whose residents “spoke like bats,” and reports of the whistled language that is still used in the Canary Islands date back more than six hundred years. Most of the forty-two examples that have been documented in recent times arose in places with steep terrain or dense forests—the Atlas Mountains, in northwestern Africa; the highlands of northern Laos, the Brazilian Amazon—where it might otherwise be hard to communicate at a distance. All are based on spoken languages: Kuşköy’s version, for example, adapts standard Turkish syllables into piercing tones that can be heard from more than half a mile away. The phrase “Do you have fresh bread?,” which in Turkish is “Taze ekmek var mı?,” becomes, in bird language, six separate whistles made with the tongue, teeth, and fingers.

For Güntürkün, whistled Turkish was not only a fascinating cultural oddity but also an exciting natural experiment. How, he wondered, does the brain handle a language that renders words as something like music? Although neuroscientists have long understood that brain functions do not divide cleanly between the left and right hemispheres, the left hemisphere appears to play a consistently dominant role in our understanding of language—regardless of whether the language is tonal or atonal, spoken or written, signed with the hands or clicked with the tongue. The right hemisphere, meanwhile, seems to govern our understanding of pitch, melody, and rhythm. In Kuşköy, Güntürkün tested this cranial division of labor by recruiting thirty-one volunteers, all fluent in both spoken and whistled Turkish, to listen to pairs of different syllables played simultaneously through headphones, one in each ear. When he gave them spoken Turkish, the participants usually understood the syllable played through the right speaker, suggesting that the left hemisphere was processing the sound. When he switched to whistled Turkish, however, the participants understood both syllables in roughly equal measure, suggesting that both hemispheres played significant roles in the early stages of comprehension.

Although the technique that Güntürkün used, called dichotic listening, isn’t as precise as laboratory techniques for measuring brain activity, his results, published in today’s issue of Current Biology, are tantalizing. “They tell us that the organization of our brain, in terms of its asymmetrical structure, is not as fixed as we assume,” he told me. “The way information is given to us appears to change the architecture of our brain in a radical way.” He now wonders whether people whose spoken-language comprehension is damaged by a left-hemisphere stroke could learn to understand a whistled dialect, much as some people with stroke-damaged speech can communicate by singing.

The opportunity to study whistled Turkish, however, is fading. In 1964, a stringer for the Times reported that children in Kuşköy were learning to communicate by whistling before they started school, and that both men and women regularly gossiped, argued, and even courted via whistle. Three years later, a team of visiting linguists observed that whistling was widely used in both the village and the surrounding countryside. But Güntürkün found that few, if any, young women had learned the language, and that, although some young men were fluent whistlers, they had learned the skill as teen-agers, more out of pride than any practical need. In recent years, the town has organized a whistling contest to encourage both tourism and cultural preservation, but the bird language is rapidly disappearing from daily life. In a small town filled with nosy neighbors, texting affords a level of privacy that whistling never did.

From time to time, though, whistled Turkish still comes in handy. When the residents of Kuşköy call Güntürkün’s university office, they often reach his secretary, who speaks German. When that happens, he says, they know exactly how to make themselves understood: they just whistle.