By default the upload wizard is asking description only in the interface language of the uploader. Most newbies, especially non-European, give the description only in their own language not understanding that a description on English should also be provided, because the upload wizard does not say anything about it. I suggest that by default description would be asked both in English and the interface language of the uploader. When looking at possible copyvios at new files it's making the check of files a lot harder when there is no description in English.
It would be best to configure this somehow - maybe with "descriptionLangs", a new array in the UploadWizardConfig that accepts iso639 codes and a set of special strings (like "USERLANG" or "INTERFACELANG" or "WIKILANG") for variables.