High Prussian (Hochpreußisch) is a group of East Central German dialects in former East Prussia, in present-day Warmian-Masurian Voivodeship (Poland) and Kaliningrad Oblast (Russia). High Prussian developed in the 13th–15th centuries, brought in by German settlers mainly from Silesia and Thuringia, and was influenced by the Baltic Old Prussian language. High Prussian is a Central German dialect formally spoken in Prussia. It is separated from its only adjacent German dialect, Low Prussian, by the Benrath line and the Uerdingen line, the latter dialect being Low German. This was once one of the, if not the hardest linguistic border within the German dialects. It shares some features with Low Prussian, differentiating it from other Central German dialects east of the de. Those Borussisms are: Loss of /-n/ in infinitives (mache for Standard German machen, "to make"); retention of the prefix //ge-// in the participe perfect passive (compare Meckelenburg German hei is lopen to Low Prussian he is jelopen) (This is common in Central and High German, but rare in Low German); overly open pronunciation of /ɛ/ (schnall, Ack - schnell ("fast"), Eck ("corner")) delabialization (Kenig, Brieder, Freide, Kreiter - König ("king"), Brüder ("brothers"), Freude ("friends"), Kräuter ("weed")); nuscht in stead of Standard German nichts ("nothing"); and preference for diminutive suffixes (kommche, duche, Briefchedräger, and Low Prussian de lewe Gottke - kommen ("to come"), du ("you"), Briefträger ("post man"), der liebe Gott ("dear God")) - and diminutives without umlaut (Hundchen, Katzchen, Mutterchen - Hündchen ("small dog"), Kätzchen ("small cat/ kitten") Mütterchen ("mother/ elderly woman")). J. A. Lilienthal, a teacher from Braunsberg, first recorded the term "Breslauisch" for High Prussian as an endonym in Warmia in 1842. Thereafter, it was considered obvious that Warmia was settled by Silesians, who brought their dialect with them. Based on a comparison of toponymy, at least for Oberländer, Thuringia was seen as a potential origin, too.