Usually I am against vocal music during gameplay (cut scenes are something different). It can distract a lot from actual gameplay. This is worst in an action game where you have to react fast and maybe listen to things other people say. D:OS is a turn based game so you never have time pressure, but voices can still be annoying, especially if you hear the same thing all the time.
However there are some good examples for vocal songs during gameplay:
- many tracks from "Beyond good and Evil". One of the few games where I downloaded the soundtrack and listen to it often. The music of bosses (the DomZ) used some alien nonsense lyrics, other tracks used different real world languages.
- The mage tower in the swamp in Realms of Arcadia3. I do not know what they sing (is it latin?), but it creates a great atmoshere. I made a save so I can listen to it whenever I want. I think it was re used for Drakensang, but I like the original version more.
- I think in FF10 the final battle with sin had heavy metal music with lyrics.
- "Still alive" from portal is a great song, but this is the ending, not gameplay.
Maybe there are some more good examples. From those, only the music from RoA3 may fit to D:OS2. It is for a dark dungeon where a mad mage makes experiments to create monsters (half man and half dog) and who has lots of undead as servants. BGE is modern electronic music and FF10 is heavy metal. I like both kinds of music, but they do not fit the typical middle age fantasy game.

Prof. Dr. Dr. Mad S. Tist

World leading expert of artificial stupidity.
Because there are too many people who work on artificial intelligence already