Tho, even the dialogue translation is possible into dub, the context behind the joke is lost due to cultural difference. If Yuuichi were to re-do that scene of Ayu saying "I
AM Ayu." in dub, many westerners wouldn't get the joke, cause over here, girls talking like a boy is quite norm. and companies wouldn't reject her because of that. So I think for most western watchers, they would be like, huh? o.O
Anyway, this type of discussion should've really gone to
http://forums.animesuki.com/showthread.php?t=39958 - Kanon (2006) Voice Actor Appreciation & Discussion thread.