Sounds good, I guess.

But I always assumed that the characters in-game were not actually speaking English to me, but that it was a proxy for Eorzean language just so the players could understand. Now we're adding more real-world languages and it's just confusing.

The Garleans speak Latin, right? So with the song in Latin, are we supporting the Garleans in their conquest of Eorzea?

I'm over-thinking things, sure... but why not just use actual Eorzean language for the trailer music?