I'd go for Theusz Hamtaahk by Magma. Not just non-English, but non-Planet Earth, as it's sung in Kobaian, an 'alien' language their drummer made up. It's a work of genius.
This song is quite heart wrenching to listen to when you realise what it's about. It's called "L' Aigle Noir" by the French singer Barbara. The title is translated as "The Black Eagle" and it"s about the sexual abuse she suffered as a child at the hands of her father. https://youtu.be/d9cEY13bUTo