Now that it is possible to change content language of any page in a wiki and thus have translatable page in different languages Special:LanguageStats became a bit messy (For instance on Meta-Wiki). Messages with the source of English, French, Japanese and whatnot are listed together. While some translators may know a scary deal of languages and not mind this, most can translate only from some of the languages, thus it should be possible to filter all the listing to just messages with specific source language(s).