As far as currently-unified language goes, we've got a pretty solid example that most places are able to communicate: The Garlean Empire. We're able to understand them when they speak, and while there's perhaps a grudging degree of respect out of Gaius, we know that Nael held NO care for Eorzea at all, yet we could understand Nael too.
We know Garlemald holds most? all? of the outside land, and they speak the same thing we all do. Sounsyy showed that there are other languages, but they're likely not commonplace.
We know Garlemald holds most? all? of the outside land, and they speak the same thing we all do. Sounsyy showed that there are other languages, but they're likely not commonplace.