at the moment no. this is because we are bypassing the region lock. if you play a U game on an E console, E consoles have english spanish and french, so if the U game were to have those languages, and your E console was set to one of them, you would be ok.
as in, you have a 3ds game from the USA, it has english and spanish as the languages. you cannot select the languages, it reads the system language from your 3ds console.
if you load this rom on a european 3ds, you should be ok, as if you wanted to play that game in spanish, you could simply set your 3ds language to spanish.
BUT, if you had a japanese 3ds, and wanted to play the game in spanish, there is nothing you can do, since you can only select japanese as your language for your 3ds system.
although, i thought in bravely default you could change the language 'manually'? so there shouldn't be a problem for that game... i think?