IAmSinistar: Ah, I thought they were infamous for not providing the German translations. Perhaps that was someone else. Or folks were highly upset at these two omissions.
It was Daedalic alright. Deponia 3 initially shipped without the German language (and the game was released 1 month later on GOG than other stores) and was added months later. When asked why Chains of Satinav and Memoria were released on GOG without German language, Daedalic gave two different explanations:
1) There is no regional pricing in GOG (Obviously, not true anymore)
2) Deep Silver holds the rights for the German language, since they are distributing the retail versions in Germany (That doesn't explain, though, why Steam has German for both games).