Let's see...
-Das Wandern from .hack//SIGN (
here are the lyrics with grammar notes)
-Hulle Granz Cathedral from .hack//G.U. (
same deal here)
-Aura actually has a leitmotif that provides essentially the same lyrics to The Hope of Dawn (in G.U.),
Aura's Theme, Macha Appears, and the Ending Theme (in .hack//)-Hidden Forbidden Holy Ground is I think the same leitmotif but drastically altered as a canon (
link)
-There's a new Hulle Granz Cathedral theme in Link that still just uses the Epitaph for lyrics.
I think for the most part the other non-Japanese songs are in a somewhat made-up Old Icelandic-based language like the original Lost Ground names, at least they said they are, but I don't have a great ear for German so I may have missed something...
Actually I can take a swing at AIKA:
La, AIKA, La~ah
La, AIKA, La~ah~ah
Alle Macht zerfällt zu Tropfen unter dem Tempel von Arche Köln
La, AIKA, La~ah
La, AIKA, La~ah~ah
Alle Macht zerfällt zu Tropfen unter dem Tempel von Arche Köln
La, AIKA, La~ahAnd in this case, maybe the selection of lyrics actually makes sense...