In at least 80 cultures worldwide, people have developed whistled versions of local languages. UNESCO has designated two whistled languages, in the Canary Islands and in Turkey, as intangible cultural heritage. In an extensive article, Smithsonian Magazine explains that whistled languages are almost always developed by cultures that live in rugged, mountainous terrain or in dense forests because whistled speech carries much farther than ordinary speech.
Read the full article at Smithsonian Magazine.