Whistle speech
I just learned something interesting about the language of the Pirahã people, who are a group indigenous to the Maici River area of Brazil.
“The Pirahã people communicate almost as much by singing, whistling, and humming as they do using consonants and verbs.” See this site for more information.
For example, they have hum speech, which is used for privacy, intimacy, and talking with one’s mouth full. They also have yell speech, which logically enough is used for long distance, and, less logically, rainy days. There’s musical speech, which is used for dancing and flirtation and apparently is more common among women than men, and there’s whistle speech, which is used in hunting and is more common among men. Apparently there are some conversations that can be conducted entirely through whistling.
The site above has a sound clip, but it just sounds like somebody whistling to me. I guess that stands to reason, since that’s pretty much what it is. I believe it is a non-native whistler, though, so maybe he’s not doing it right.