Hello, Until MediaWiki 1.27, any message not translated in Slovak or in Czech is printed in English. For MediaWiki 1.28, we plan to offer a fallback between Slovak and Czech languages, as these languages are easier to understand to contributors than English. The fallback is currently committed on our master branch. Than means any message not translated in Slovak on a MediaWiki installation in Slovak will be printed in Czech and inversely. This change has been prepared by Federico Leva. If you approve this change or has concerns with it, your opinion is welcome at https://phabricator.wikimedia.org/T143474. If you don't have a Phabricator account, you can use e-mail and I'll forward your opinion. -- Best Regards, Sébastien Santoro aka Dereckson