have you changed your system language to japanese just before starting the game for the first time??
bc there's no way to put the game trophie list back to english once you start the game into an other language.
edit: wait, wait, wait... is it doing it only on the website? or it's show in your trophy collection on your PS3 too?
LOL no I did not change my settings to japanese. You silly! I got all my other games that are working perfectly on this website and my trophies are in english on my PS3 Trophies section but on this website it's in japanese.