The profile has an option to set the language used on the forum to dutch. I tried checking it out, but it generates a lot of errors AND misses a lot of options, including the option to visit your profile page, which you need to set it back to a working language. I was able to fix it, but going a couple of pages back, but others might be less lucky.
Perhaps the language could be removed to prevent people from entering a screwed language setting, which they cannot undo.