Their translation tool needs something like a user editable drop box system...
so when the translation tool comes across a word with multiple meanings depending on the context, it'll present instead of a single word, a drop down box of correct alternate meanings...
users can then go in there and select or even add the relevant words, putting them into a database and then ranking them in terms of how different translations stack up against each other.
Also, the users can select several contextual meanings to the page to be translated, and the words are automatically defined according to that context... but still allow for the user to change them accordingly.
Of course, the translation interface would default to giving users plain text of the highest ranked translation of the site, but would be like viewing pictures, with the google toolbar uptop, giving options to contextualize/edit the text, view other translations of the text and what not.
Eventually, over enough time, most established websites will be relatively accurately translated into most languages.