I understand why Stack Overflow is English-only, and agree with this, but in the response from Jeff to an interesting suggestion from Oscar Reyes, he notes that "for Stack Exchange, this is a different story".
Take for example the Woodworking and Carpentry proposal. I would love such a site, but since the jargon is different in each language, I would have a hard time participating in it without the risk of losing one or more fingers due to misunderstanding of some key terminology. On the other hand, it would be a shame if this (maybe not so large) community would be fractioned by language, while we could create some tools to bridge the gap (I can imagine an automatic integration with Wikipedia articles, and their inter-wiki links, for certain key words, e.g. "Take your chisel (beitel) and work on the last part of the dovetail (zwaluwstaart)".
Imagine if we could harvest the power of the multilingual experts by letting the communicate not only in English, but also in other languages with less experienced people. Or all the experts who don't speak English, but are not numerous enough to form separate communities. Could the idea from Oscar, combined with some extra tools, create an environment where they can all contribute?