He is employed as a Professor at the Institute of Germanic and Nordic Studies of the Jagiellonian University. His research interests include the broad history of the German language, the history of German settlement in Polish lands with a particular focus on Silesia, the history of Cieszyn Silesia, onomastics, German dialectology, and Polish-German cultural and linguistic contacts. He is the author of books and numerous scientific articles on the Silesian dialect and German language enclaves, such as Bielsko or Łańcut, and the co-author of many editions of Silesian German source texts along with historian colleagues.