uses en and de sub directories below root. For building two different configs are used, reflecting the according baseurl for each language. You can switch between languages on page level.
After deploying nginx is taking care redirecting root to the language directory of the language to start with.
The key here seems to be two use different config, since else it would mix up diifferent content languages.
As soon as there is some spare time I'll put the theme and some documentation, how everything is set up on github. Might take a few days though.