Dietsch ("Diets" in modern Dutch)'s a colloquial word for the Middle Dutch language. In a linguistic context however, it specifically refers to the southern Middle Dutch dialects such as Brabantian, Flemish and Limburgish. Though even in modern Dutch linguistics it's rarely used. Diets(ch)'s a cognate of "Dutch", "Deutsch" and "Duits". In 16th and 17th century "Duits" and "Diets" were spelling variants of the same word. A modern translation for this word however would in both cases be "Dutch",… (More on Dietsch)