I still think Urianger is just putting on an act or trolling or something. That takes some genuine effort to maintain that speech pattern despite literally nobody else anywhere ever speaking in a similar manner. Worse, he explicitly knows the people around him often have some minor difficulty in deciphering what he's saying, and yet still insists on being as archaically verbose as possible.
Dude's been in Eorzea long enough to pick up on the fact that he should probably consider learning how to converse with the locals a bit more efficiently.