She's not going "Yeeeeeeeah;" it's far more similar to when you might hear a singer go "Laaaaaa" just with your tongue placed differently differently and breathier, like the louder, heavily stomach-based singing of an opera. That's the best part of the song, quality-wise, in my humble opinion.
Because it's not found in a lot of western music, I can imagine it sounds quite strange to those unused to it. I, however, adore it. They've used Mongolian Throat Singing with Ravana, I wouldn't be surprised if they went full Akiko Shikata on us eventually.
Have a (rather extreme) battle variant of nasal chanting, because when giving an example, I have to go all out in craziness -
https://www.youtube.com/watch?v=eoicX3RPf5Q
tl;dr
I was really disappointed by the Ramuh song because it went so. . .boring after the intro teased me with nasal chanting.
That and the Engrish.