Well, that's because the voices can't adapt to whatever you name him
I know....it still felt strange. After a while, I just started laughing everytime somebody went, "Hi, I'm Wakka, and this guy is my friend." And the only introduction Yuna ever got to the man of her life was "Oh, and he's here too." I get the technological limits, but I still find it awkward storywise. Add neverending final boss battles to my list of things I don't love about FF. Those evil people take hours to kill.