When you, a human, want to audibly communicate with another person, you generally use your voice. Speech happens when air passes through your larynx, or voice box, and amplifies the noise made there in your throat, nasal passages, sinuses and mouth. This is a great way to communicate, but there are some drawbacks.
For instance, if you live on a mountainside and your friend lives one slope over, shouting to each other isn't always that effective. For one thing, shouting creates a lot of echoes among the nooks and crannies of mountain slopes, and the average outdoor range of an intelligible human voice is only about 591 feet (180 meters). Short of walking over to where your friend lives to carry on a conversation at a reasonable speaking distance, or communicating with some sort of visual technique like smoke signals, there's not much to be done except to whistle.
Whistling is the product of air being forced through a small hole made by your lips. A whistle is different from your voice because it is clear, and the frequency is narrow and high-pitched. The sound of a whistle can carry for more than 5 miles (8 kilometers) and it holds its form, while a shout can splinter into an echoey mess. Birds have discovered this and use it to communicate between treetops and mountainsides the world over.
So, although humanity has relied on spoken language for millennia to accomplish everyday, face-to-face communication, there are more than 70 groups around the world that engage in special whistled languages — millions of people speak them, although the advent of text messaging has certainly seen a dive in whistled language worldwide. They're most commonly found in mountainous regions where shepherds or farmers need to pass messages around without huffing and puffing up and down hills to do it, but whistles are also used to communicate through the impenetrable undergrowth of the Amazon rainforest and are useful to Inuit at sea as well.
Hunters can use whistling to speak to each other in a way that doesn't alarm their prey like voice-produced language might. Whistled languages have even been useful in battle among soldiers fighting on the same side.
"The most fascinating thing about whistled languages is their birdlike aspect which encodes the complexity of human languages while highlighting a tight relation between human language and the environment," says Julien Meyer, a researcher at the University of Grenoble in France and author of "Whistled Languages: A Worldwide Inquiry on Human Whistled Speech."
According to Meyer, when whistled speech is still present, it signals that traditional activities are still commonly practiced and therefore a relationship with the land is maintained.
How Whistling Languages Work
According to Meyer, whistled languages are commonly based on the spoken language native to an area. For instance, in Southern China, where the diversity of whistled languages is high, spoken language is tonal — that is to say, the consonants and vowels decide the meaning of a word, as well as the pitch. The whistled languages in this part of China seem to match the musicality of the local speech, and the pitch of the whistle can change the meaning of a whistled "sentence."
In places where the language is not tonal — like in the mountainous Canary Island off the coast of Spain where the whistled language Silbo Gomero is "spoken" — Spanish acts as a template for the sounds of their whistled language. The vowel sounds are mirrored in the shape of the whistles while consonants are decided by the clip, cadence and slides of the whistled tones. To hear it, it seems crazy that anyone would be able to understand Silbo Gomero at all, but according to Meyer, whistled language speakers around the world are found to be able to understand about 90 percent of what's communicated.
Whistled Language in the Brain
Meyer conjectures that people are able to understand whistled language for the same reason you can read a sentence full of words whose letters have been jumbled: Our brains are desperate to make sense of what's going on.
Whistled languages have some neuroscientists rethinking how language works in the brain. It's been commonly thought that language is the exclusive purview of the left hemisphere of the brain, but studies of whistled language speakers have found that these languages are handled by both sides of the brain, much like music.
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