Highly enjoyable. Interesting idea using a custom chosen set of syllables that don't intentionally exist as words in any language, let's any listener enjoy the "foreign" feel regardless of their native language. The song structure is nice and varied and you produced a wide range of sounds with your mouth!
As for things to improve i think the voices sounded a little weak/quiet. I'm not quite sure what it is but i felt they didn't quite fill the sound space. Perhaps some equalizing or different panning might fix it but i can't say. The part at 1:50 sounds better and at that point i was really getting in to the song. A wonderful medley of wonderful melodies! The singing was all nice and soft on my little ears and the panning at 2:58 really felt like you were singing just next to my head, spooky.
Overall i think you did a good job with this. It's fun, creative and unusual and for that it gets a 10!