Those are the default names; once you create the pages, it would be a good idea to stop using the default page names. See < http://www.mediawiki.org/wiki/Manual:Interface/Sidebar > for details on doing that.
As a summary, go to [[MediaWiki:Sidebar]], and then create pages for the words that appear in it. For example, where it says "currentevents-url|currentevents", creates [[MediaWiki:Currentevents-url]] and [[MediaWiki:Currentevents]] with the link target and title you want.
The translations are provided by volunteers on < http://translatewiki.net/ >, and they're likely not on this mailing list at all.