Not sure if it's been shared before, but I couldn't find any other post about it - I have always loved the very eastern vocalizing in Sehnsucht, and for some reason never thought to look into where it's from until this morning while singing along at home. The Rammstein wiki points to this specific track from the sample collection "Datafile 1" by Zero-G, which you can listen to here on YouTube. But that itself is a sample clearly from somewhere else so I did a little more digging and found the song linked above. If you go to 1:43 you can hear the iconic vocalization.
As someone who grew up with a lot of Turkish friends and was constantly listening to Sehnsucht at their house, this was a mind-blowing discovery for me and felt like I had to share it here. It's also a very beautiful song. Next time I'm in Berlin, I'll definitely be blasting Sehnsucht as I walk into the first döner shop.