Bah, you people are weird. I'll explain it:

After Ocarina of Time was released, an expansion to it was developed for the N64 disk drive system, which was intended to expand the capabilities of the N64 by adding storage space. The drive failed miserably, and never saw the light of day outside of japan.

When Wind Waker launched in japan, the disk drive version came as a pre-order incentive. Nintendo announced it had no plans to release the incentive with wind waker for the north america release. People were quite pissed, so they changed their minds and did the same here. The add-on is just like any other japanese game launched in other countries, it'll be fully translated.