I was under the impression that the language choice was just a cosmetic thing.

That if you picked E or J, or whatever. It was just a social cue to let your other players know that you don't speak their language. You know, so if I try talking to some smuck, and find out that they're only J. Oh, they're not English, alright. I figured the letters are just there to communicate information. And that it had zero influence over the actual mechanics of the party finder.