Ability to set language of administrative backend

When working on a multi-language install the language of the administrative backend keeps switching whenever the country code is in the url. I am using 'path prefix' to choose the language. It would be nice to be able to set the language of the administrative backend regardless of the languages installed in a multi-language install.

'Site configuration' -> 'Languages' -> 'Configure' might be a good place as people will look there for the language settings. Alternatively something like 'Site configuration' -> 'Languages' -> 'Admin language' might be more intuitive and quicker to spot. The name could probably be better as admin's would probably only pick up on this, if that.