Thanks to sandor.adi and Erika, there is a slovak translation file available for download here (location will be moved as soon as the eXchange application is available).
As the charset is set to ISO-8859-15 in the file itself, it shall work with UTF-8 as well.
Great to have a community like this
Marco Steinhäuser
Community Guide
OXID eSales AG
http://twitter.com/marcosteinhaeus