Microsoft Office 2013 Slovak Language Pack ((free))

Users sometimes confuse a full Language Pack with "Proofing Tools." If a user only requires spell-check capabilities in Slovak but wishes to keep the UI in English, they do not necessarily need the full Language Pack. Office 2013 often includes a "Proofing Tools" kit that installs dictionaries for multiple languages without altering the interface. However, if the goal is to have Slovak menus, the full Language Pack is required.

With the language interface set, you should also configure the default proofing language: Microsoft Office 2013 Slovak Language Pack