|Extinct||Early 18th century|
|Revival||Attempted revival, with 50 L2 speakers (no date)|
Old Prussian was a Baltic language spoken in what is now northeastern Poland and the Kaliningrad Oblast of Russia. It was spoken by the indigenous peoples of Prussia, the Old Prussians. It declined after the Teutonic Knights conquered the territory in the 13th century but was spoken until about 1700 in and around East Prussia. It was named Old Prussian to show that it is different to the Slavic and Germanic languages used in Prussia afterwards. It became extinct in the early 18th century. Attempted revivals have made little progress.