I’ve just watched a recording of a Joanna Lumley series on Greece which showed some of the whistlers of Antia. Apparently this language has been practised for centuries but the last whistlers will probably and sadly be this generation (some 40 villagers).
The art of whistling is something I’ve always envied.
http://www.crystalinks.com/whistledlanguage.html
Whistled languages are a form of communication used by many indigenous people around the world. The languages differs according to whether the spoken language is tonal or not, with the whistling being either tone or articulation based. Tonal languages are stripped of articulation, leaving only suprasegmental features such as duration and tone, and when whistled retain the spoken melodic line. In non-tonal languages, some of the articulatory features of speech are retained, though the normally timbral variations imparted by the movements of the tongue and soft palate are transformed into pitch variations.
Thus whistled languages convey phonemic information solely through tone, length, and, to a lesser extent, stress, and many phonemic distinctions of the spoken language are lost. “All whistled languages share one basic characteristic: they function by varying the frequency of a simple wave-form as a function of time, generally with minimal dynamic variation, which is readily understandable since in most cases their only purpose is long-distance communication.” (ibid: 32)
Languages communicated by whistling are relatively rare, but are known from around the world. One example is the Silbo on the island of La Gomera in the Canary Islands, which maintains Spanish’s five vowels, but reduces its consonants down to four. Others exist or existed in all parts of the world including Turkey (Kusköy “Village of the Birds"), France (the village of Aas in the Pyrenees), Mexico (the Zapotecs of Oaxaca), South America (Piraha), Asia (the Chepang of Nepal), and New Guinea. They are especially common and robust today in parts of West Africa, used widely in such populous languages as Yoruba and Ewe. Even French is whistled in some areas of western Africa.