I do believe that the option to have Yorda's dialogue translated opens up after playing through the game once. The same feature was planned for the English release, but, I don't know, it didn't happen. They probably ran out of time.

Quote Originally Posted by FallenAngel411
Also, there is a courtyard at one point during the game (the waterfall puzzle) where if you hit a tree with your sword, a ball drops out of it. You can pick it up and carry it around. It seems pretty random, and I was wondering if anyone else has found this and knows what it is. I heard something about alternate secret weapons that you can find for Ico (lightsaber and mace), and I was thinking that the ball might be part of the mace or something.
Yeah, you're pretty much right. You have to do something with the ball to get a secret weapon - check out GameFaqs for a walkthrough.

O yeah....and just heard about the sequel too....called "Wanda and the Collosus". I heard they're wondering whether or not to bring it to the US, since ICO didn't sell very well when it was released. So all us fans have to rally and make sure they bring it over here! I shall die if I don't get to play it!!!
It's not a sequel, but I'm still really looking forward to it, and I hope it sees an English release.