After manually upgrading an existing c5 installation from 5.5.2.1 to 5.6, on the dashboard's System & Settings page, Basics, the Languages item has vanished away.

I have doublechecked some database tables related to pages with another clean 5.6 installation (as far as my skills allow), and i also reuploaded all files in the concrete folder, cleared the cache, refreshed core database tables and blocks, but still no "Languages" item.

Can anybody figure out, what could have happened or which db table or which files i would have to check?