This recently-released patch is a translation of Ultima 8 (specifically, version 2.12, or the Enhanced CD version; if you’re playing the GOG version of the game, this patch will work) into Spanish.

Although the audio from the Speech Pack hasn’t been translated, all of the in-game text will be rendered in Castilian. Given the length of some of the translated phrases, it is recommended to adjust the text speed in the game’s options to a slower setting than the default. When you install the patch, you will be prompted to specify the location of your Ultima 8 installation, and will then be presented with three options: install the translation only, install the translation and the tools used to create it, or install the translation with support for the Ultima 8 Speech Pack.

A few bugs, such as the issue with the key to Devon’s chest, are also corrected in this patch.

It’s worth noting that L@Zar0, the patch author, created his own tools for extracting graphics from Ultima 8, adding new fonts to the game, and modifying/translating in-game text. He has generously included all of these with the translation patch, in case others want to make use of them to translate the game to other languages.

You can grab the installer for the patch at the new project entry for it here, or via this forum thread at Clandlan.