Sudovian (otherwise known as Jatvingian or Yotvingian) is an extinct western Baltic language of north-eastern Europe. Closely related to the Old Prussian language, it was formerly spoken in Galindia and Sudovia in Prussia. Sudovia and Galindia were two of the twelve original Prussian lands. Not actually a separate language, Sudovian, Jatvingian has however been documented in writing and therefore this Prussian language is listed here.

The southern Prussian districts of Sudovia and Galindia were partially overtaken and conquered by Slavs around present-day Bialystok and Suwalki in north-eastern Poland and nearby Hrodna (formerly Grodno) in Belarus. Some elements of the Baltic language are still retained in the Belarus and Ukraine territory due to settlements of refugees and prisoners from Prussia.