We've just done a report for one of our clients comparing Drupal, Joomla & Wordpress for (1) multilingual capabilities (also called internationalization or i18n); (2) end-user usability; and (3) developer usability.
As a national organization in Canada, being bilingual was a must. Check out our CMS comparison.
This is a good report and I'll let you read it on your own to find out which CMS they recommended the client utilize for their next CMS. I like the fact that the analysis compared criteria consistently and observed pros/cons in each of the Web applications.
I also find it interesting that they referenced a post I did last year comparing Drupal and Joomla as well as an article from Gadgetopia's Dean Barker. It's interesting in that both Dean and I have both gotten a lot of mileage out of those posts and it shows just how much we all feed from each other when it it comes to writing about information technology.
Bryan Ruby is the owner and editor for CMS Report. He founded CMSReport.com in 2006 on the belief that information technologists, website owners, and web developers desired visiting sites where they could learn about content management systems without the sales pitch. Besides this site, you can follow Bryan at Google+ and Twitter.