Polabian
The Polabian language was a group of slavic dialects spoken in present-day northern Germany - Mecklenburg, Brandenburg, Saxony-Anhalt, eastern parts of Lower Saxony and Schleswig-Holstein. Became extinct in the 18th century. There are known Polabian texts writen in Hanover Wendland (Luechow-Dannenberg) in XVII and XVIII centuries. Polabian was one of the Lekhitic languages.