There is the language files which can be edited...,not sure if anything in there will affect what shows up on the "recent" page or any of the other virtual pages.

The "recent" page uses header.tpl and footer.tpl as well as submenus so If you make those German, then the page should be in German. Any videos put on the site will show up as they were uploaded (if the titles were German, then they would show in German).

"Added/by/Time/Views/Comments/Not Rated/" appears in several of the template files, I'm guessing you'd have to change the code on that part, to German, in each of the templates or maybe check the database...not sure. The only time I had to monkey with that was when the script used to show the time in seconds rather than minutes and seconds.