Turkish has a whistled version, used often in the mountains of northern Turkey. It’s eerie and lovely, and seems to do interesting things to the brains of people who listen to & understand it.
https://www.sciencenews.org/article/whistled-language-uses-both-sides-brain?tgt=nr
Why am I excited to blog about it? I have another data point for ‘singspeech’, my made-up Sonnaroi constructed language. Think four separate vocal cords and big chest cavities, as well as long nasal passages and tongues to help modify sound. I ‘hear’ this non-human language as a combination of higher-pitched whistles and deep-toned calls. The language goes higher and lower than humans can usually detect. A human, standing in the middle of a Sonnaroi tribal conclave, would probably only hear a little bit of the debate going on around her. She might ‘feel’ more of it, just as we can feel the deep rumbles of elephant calls.
Sonnaroi, in my made-up universe, are deceptively primitive hunter gatherers. They’re a bit shunned and discriminated against by the more human-seeming civilizations on their planet. But Sonnaroi keep a lot of very important secrets, including a verifiably-accurate spoken history going back more than a million years.
This, right here, this is why I tell new fantasy and science fiction writers to read and watch more non-fiction. We can build so much more vividly from solid, real-world foundations!