Just as Hingans speak the in-game equivalent of Japanese I have little doubt that Pureblood Garleans speak the in-game equivalent of Latin. It is but a question as to whether the language is taught in-depth to citizens and conscripts of Garlemald. It could be something fairly exclusive - nobody is really taught Latin in the UK if they go to a state school but it's very common for it to be taught at private schools. (You can imagine my puzzlement when I graduated and realised that only a tiny portion of the population actually spoke Latin! Yet I digress...)