The Oder is a river in Central Europe. It is Poland's second-longest river in total length and third-longest within its borders after the Vistula and Warta. The Oder rises in the Czech Republic and flows 742 kilometres (461 mi) through western Poland, later forming 187 kilometres (116 mi) of the border between Poland and Germany as part of the Oder–Neisse line. The river ultimately flows into the Szczecin Lagoon north of Szczecin and then into three branches that empty into the Bay of Pomerania of the Baltic Sea.

Kashubian or Cassubian is a West Slavic language belonging to the Lechitic subgroup along with Polish and Silesian. Although often classified as a language in its own right, it is sometimes viewed as a dialect of Polish.