Years ago I was in a pub in (on?) Cowgate in Edinburgh. Everyone was drunk and drinking and having a good time. And there was music. Then a bunch of German folk got up, they were dressed in Lederhosen (it was during the festival), and started singing, in German. There was cheering and much jollity but all I could think was "I don't know what they're singing... this could be 'Tomorrow Belongs to Me'"
And that's always the problem I have with music sung in languages I don't understand (which is every language except this one!). A few years back I expressed this concern to Hazel in regards to Juana Molina and she laughed at me "she's like an Argentinian Victoria Wood" she replied!
Despite these concerns I listen to a lot of music in other languages, and love lots of it, convincing myself that if I like it, it's probably OK.
I like Los Planetas rather a lot, they make fizzy 90s indie guitar music. I'm fairly confident that their lyrics aren't about world domination.