The following is a mediawiki feature request concerning improvements to make cross-language cooperation and translation more attractive. I also posted it to the enormous feature-request- and bug-report-wiki on meta, which is probably better to read, because of the HTML formatting. (http://meta.wikimedia.org/wiki/MediaWiki_1.3_comments_and_bug_reports#Featur...)
The unfortunate fact is that today the wikipedias reinvent the wheel for every language. The only relationship that sometimes exists, is that articles get translated from one language to another. Each of the changes that are then made in both versions of the article benefits only the wikipedia of one langauge.
This is not only a problem for the smaller wikipedias. Especially local information is much better represented in the wikipedia of the regional language, and it would be beneficial for the english wikipedia, if that information were to be imported. Also some pages (I only know about german) in foreign language versions are written from an interesting other perspective or just have more work done, because some people speaking that language happened to be very interested in the subject.
The reason why I personally don't translate wikipedia articles, is because I feel that instead of benefiting wikipedia, I split up the manpower between the english and the german version. This would change, if the work in one language would benefit the wikipedia of another.
What I suggest is:
(1) The possibility to maintain a relationship to the link of the article in other languages, like - translated from (this article is a translation of the article in that language) - translated to (this article has been translated to that language) - independent (the content of the article is language specific) - unmerged (no translation in either direction known) - merged/corresponding (people work on the article in both languages, changes in both articles get applied to the other one)
(2) A counter that counts up from the last edit made with a special keyword, an trans-lingual edit could then be called something like "cross-language [german] in: Added new section, out: rearrangement of introduction". Such a counter could either count the changes made in the other language, the changes made in this edit, both added up, or preferably both beside each other to get a glimpse on which one is more dominant.
(3) A special page, that lists the topics that have the highest counter between this and another language, for people interested in translating articles.
The better the articles get, the more sense does it make to translate the content. Making translation more attractive is beneficial for both the main (adding local information) and the language (more/higher quality content) wikipedias.