Day 177 — Reading: Talking Across Valleys — What Whistled Languages Reveal

Talking Across Valleys: What Whistled Languages Reveal

AOn the Canary Island of La Gomera, a farmer standing on one side of a deep ravine can still send a detailed message to a neighbour on the other side without raising her voice or reaching for a phone. She does it by whistling. The system she uses, known as Silbo Gomero, is one of more than eighty whistled forms of speech that researchers have documented around the world, from the mountains of north-eastern Turkey to the forests of the Amazon and the highlands of southern Mexico. Most of these communities share a landscape of steep slopes, dense vegetation or scattered settlements, where a shout fades quickly but a sharp whistle carries for one or two kilometres, and in the right conditions considerably further.

BIt is tempting to describe such systems as separate languages, and travel writers frequently do. This, in my view, is a mistake. A whistler on La Gomera is not using a vocabulary of his own invention; he is speaking Spanish, transposed into a different kind of sound. Listeners who know no Spanish cannot follow a whistled conversation, however carefully they have studied the whistles themselves. A more accurate comparison is with writing: just as a written sentence is English or Arabic rather than a separate language called 'ink', a whistled sentence belongs to the spoken language it encodes.

CHow that encoding works depends on the spoken language. In tonal languages such as Mazatec in Mexico or Yoruba in West Africa, the pitch of each syllable already carries meaning, so the whistler largely reproduces the melody of the sentence, along with its rhythm and the length of its syllables. Non-tonal languages pose a harder problem, because their vowels and consonants are distinguished by the shape of the mouth rather than by pitch. Whistlers of Spanish or Turkish solve it by converting the changing resonances of the vocal tract, which a phonetician would call formants, into rising and falling pitch. Much detail is inevitably lost. Linguists disagree about how many distinct vowels Silbo preserves – estimates range from two to five – and listeners rely heavily on context to recover what the whistle leaves out.

DThat reliance has made whistled speech interesting to neuroscientists. For more than a century, the left hemisphere of the brain has been regarded as the dominant site of language processing in most people, while the right hemisphere is associated more strongly with pitch and melody. In 2015 the biopsychologist Onur Güntürkün and his colleagues tested listeners from Kuşköy, a farming village in the Black Sea region of Turkey whose residents call their whistled Turkish kuş dili, or 'bird language'. When the villagers heard spoken Turkish, the familiar left-hemisphere advantage appeared. When they heard whistled Turkish, it largely disappeared: both hemispheres contributed about equally. Admittedly, the result comes from a single community and a single language, and it would be rash to build a general theory on it. But it does suggest that the left-hemisphere dominance found in so many studies may owe something to the acoustic form in which language usually arrives, rather than reflecting a fixed property of language itself.

EThe future of whistled languages looks less certain than their scientific value. On La Gomera, use of Silbo fell sharply from the 1950s, partly as a result of economic decline, and in the following decades many families avoided it because it had come to be associated with rural poverty. Roads and, later, telephones removed much of its practical purpose. In Kuşköy, mobile phones are widely reported to have had the same effect, and estimates of how many people can still use bird language vary considerably.

FOfficial recognition has followed. Silbo became a compulsory subject in La Gomera's primary and secondary schools in 1999, and UNESCO added it to its list of the intangible cultural heritage of humanity in 2009; Turkish bird language was added to a UNESCO heritage list in 2017, and Kuşköy has held an annual whistling festival since 1997. It is often claimed that such measures have saved Silbo. They have certainly ensured that a generation of children on the island has learnt at least the basics. Yet a skill practised for an hour a week in a classroom is not the same as one used every day to summon help or to arrange the movement of animals across a valley. What schools preserve may prove to be a performance of identity rather than a means of communication.

GNone of this means the effort is wasted. Even as a performance, Silbo keeps alive a body of knowledge about how humans can adapt speech to an environment, and it gives researchers living speakers to study rather than recordings alone. The deeper lesson may be that language is less tied to the voice than we tend to assume. Wherever there is a reason to communicate and a channel that can carry a pattern, people seem able to find a way.