Other mistake: If you talk to the boy in the Kilika inn, he says, "I'm gonna be a blitzball when I grow up." Obviously, he was meant to say "blitzball player," but it was messed up in the end.
Continuity mistake: When Tidus is teaching Yuna how to whistle and says "Put your fingers in your mouth like this," he talks as if he has his fingers already in his mouth for the entire line when he doesn't actually have them in his mouth until he says the last two words.