I'm exactly the same way but I've found that sighs j-pop fits in this as well. If I can't understand the words then it doesn't break my flow. German techno also seems to work.
I like music with nonsense lyrics for the same reason, i.e. cocteau twins, sigur ros, dead can dance. Otherwise, ambient stuff like explosions in the sky, god is an astronaut, mono (the japanese mono).
Try some Godspeed You! Black Emperor
I hear you on the vocals; your brain might work like mine...I never forget a conversation and I can't tune them out no matter how trivial.