There appears to be no broad consensus among the Wikipedians about the use of minority languages in town infoboxes. It is nice that you have decided to use two languages in the case of Transylvania. But many other local infoboxes (e.g. Alsace-Lorraine, Belgium, Estonia, India, Latvia, Lithuania, Turkey) include only the name in the official language. I do not oppose a broader discussion about the Slovak towns infobox and I will be happy to implement any consensus arising from such a discussion. However, the change you have proposed should be discussed by all the relevant editors of the articles about Slovakia, not just you and me. I believe this talk page is not the most appropriate place for such a discussion.