There seems to a problem with character encodings on users' walls. For example, I had a discussion with KiigelHeart on my wall, and while the original post is OK, the comments to it are not. Specifically, ä characters cause problems, and I bet a lot of other characters do too. It seems the site uses a different encoding for the original post and the comments posted as responses to the original comment. I'm having the problem on at least Firefox and Chrome, so it would seem unlikely it's just my problem. Oh, and comments seem fine when you post them, but once you reload the page, they're messed up. I think the bug should be fairly straightforward to locate using this info (seems like the comment-posting code is using different encoding from the rest of the site).
Yeah, that's what we mean when we say support for major languages. I guess it could have been worded a bit more specifically on our end!