Hi Roman. Welcome to ThoughtStorms. Good to have you here. :-)
Thanks for your contribution. Good stuff. I didn't know about Wallop. (And sorry I managed to lose your contribution the first time.) Hope you find something useful here for you too. And remember, ArgueAgainstMe if you disagree with anything ;-)
I went to see your wiki and I need to mention that I have a similar dilemma to yours - what language to use for my personal site. You've choosed to use mostly Russian with some English outcrops and I choose the other way - English.
I have a similar problem. As I'm living and teaching in Brazil I'm learning Portuguese and I want to do my bit to help the LusoSphere. But I write in English because that's the only language I really know well enough to say anything interesting. And, of course, it lets me talk to people around the world. (ThoughtStorms is hardly a popular site, but it already has contributors from Russia, China, Poland, France, England, Germany, Ireland, US, Canada and Brazil.)
At the same time, I believe in supporting other languages and I think things like BlogaliZation are a great idea to help exchange ideas between various linguistic spheres. But what works for blogs doesn't work for wiki. And I think this is probably another example of OneWayLinks. Because blogs are one-way communication media, individuals can decide to play the role of importer / exporter of information and ideas from one language sphere to another (probably earning DownstreamCredit on the way). They only need to translate and publish to make this connection between the spheres.
In general, wiki is about multi-way interactions on the wiki. And that really requires everyone to speak the same language (to get the combinatorial explosion of everyone reading everyone else.) So there's a higher lingistic co-ordination cost to get wiki to work.
WikiPedia does manage various translations. And I suppose if one uses MediaWiki one gets better management of that. Maybe that's the answer if you're serious about multi-lingual wiki. Hmmm. Just freestyling here. Don't know the answer.