@Sander78, thanks for bringing this up. I’ve been toying with the idea to create an informal German translation but ran into the same wall.
@neil, you wouldn’t be the first person trying and failing to get to grips with the distinctions between formal and informal speech. However, I don’t believe that deciding on either one is the right approach; the differences between formal and informal may be subtle, but it sets a certain tone and different communities will want to be able to choose.
Maybe translations could be removed from the core entirely and be installed as plugins?