That's actually a really interesting question. For a human, I'd guess that it's almost impossible, at least with any precision. But with some kind of ML or AI s

That's actually a really interesting question. For a human, I'd guess that it's almost impossible, at least with any precision. But with some kind of ML or AI solution, especially calibrated for a specific person, I think it could be achievable. At least when I whistle I don't keep my mouth rigidly in the same shape no matter what pitch I'm whistling. The higher I go, the more I purse my lips; the lower I whistle, the lower my jaw is. Add in neck movements to factor in tongue and diaphragm adjustments for pitch, and you have a lot of signals to read.