Westphalian is one of the major dialect groups of Low Saxon. Its most salient feature is the diphthongization (rising diphthongs). For example, we get iEten instead of E:ten for eat. The Westphalian dialect region includes the northern part of North Rhine-Westphalia, i.e. the former Prussian province of Westphalia excluding the Siegerland and the region around Osnabrück.
