When you mod the voices, is it culture based, or faction specific?

For instance if I changed the culture of the Greeks Cities to "Roman culture", and had the Latin Voice mod installed, would the Greek Cities start talking in Latin Voices?

Furthermore, what if I'm playing a mod that has the Latin Voice mod installed, and has changed the factions, if I want to go back to the normal voice, can I just reinstall the file from Vanilla RTW 1.5 (the mod is also for 1.5) and as long as the Roman Faction has the Roman culture, the Latin Voices will be replaced by the vanilla voices correct?

I probably didn't need to write all this, as I'm nearly 99% sure it is culture based.