Speyer line

Speyer line - Wikipedia, the free encyclopedia: "in German linguistics, the Speyer line, Main line (Main river), or Germersheim line is an isogloss separating the dialects to the north, which have a geminated stop in words like Appel 'apple', from the dialects to the south, which have an affricate: Apfel. The line runs from east to west and passes through the town of Speyer. In Germany, the line is most well known by its humorous designation Weißwurstäquator."