I've been watching this 5 part documentary on India off and on for a bit and in one of the earlier installments it addressed these chants that have been handed down by word of mouth for generations through this one group of natives at this annual fire-festival. It was recently allowed to be recorded and analyzed since it didn't seem to be in any known language. So these linguists analyzed it and found some patterns and sort of laws to the sounds within it and they realized that it wasn't so much a human language as that of bird-song. So the thought is that it is a chant handed down, son to son since before there was language. How cool is that?
In any case, I mention this because the chant in your post made me think of this. Lovely post. Nice to get to Ixtab.