haha, turns out that Ovelia says it in the new Tactics anyway, but yeah, it's consistent with 12 as well 'ee-va-lee-ce
Judging from the way that it's spelled, one would probably find it most logical to pronounce it Iv-al-iss, but then again, we're dealing with voice overs from Englishmen. It's just like the an old saying... You say ta-may-to, I say ta-mah-to.
Even though that's how it was pronounced in the trailer, I refuse to pronounce it that way. : p