Last modified: 2012-06-02 08:47:25 UTC
It's now possible to pass fields (like description) to the UploadWizard to prefill fields, but it's not possible to pass the language. My interface language is English. I come from the Dutch Wikipedia with a prefilled description in Dutch, but the language selector field is still on English. lang=nl or uselang=nl are not accepted.
Maarten, could you post the exact URL you tried to use? Ideally, could you also include a screenshot of what actually happens? I can't reproduce what's happening, so I suspect you've done something that's not obvious.
And just as a reference, http://commons.wikimedia.org/wiki/Special:UploadWizard?uselang=nl works fine for me.
Tested it yesterday and now it seems to work. That will teach me to wait with filing bugs ;-) Will file a new bug (feature) to be able to set the description language in the url.