Last modified: 2014-07-08 19:20:21 UTC
de.wikipedia.org (Langsettings: de) should be redirect to the german version of Commons (&uselang=de) it.wikipedia.org (Langsettings: it) should be redirect to the italian version of Commons (uselang=en) ar.wikipedia.org (Langsettings: ar) should be redirect to the ar version of Commons (&uselang=ar) etc.
If that's a good thing, it should be used in the normal file page link as well, not just MediaViewer. The big drawback is that the language would revert back as soon as the user follows some link, which would be very confusing. I think ULS supported a setlang parameter at some point, which would be more suitable for this, but dropped support at some point. CCing Siebrand for guidance.