Wiedemanni F.J. (Ferdinand Johann Wiedemann, 1805-1887)

Linguist of Swedish-German descent, the first to describe Estonian’s peculiar opposition of three phonological quantities (for more details, ask a native, they probably won’t be able to explain either); compiler of various dictionaries (e.g. Ehstnisch-deutsches Wörterbuch (1869), Estonian-German dictionary) and grammars of northern coastal Estonian, Võru, Livonian, Syjranisch (aka Siranian, Sirenian, Sirjenic, Syrjenic also written Zirianian, a perhaps now extinct Finnish dialect of the Vologda Oblast, Russia)... Street previously (until 1923) named Lutheri under various guises (Lutri, Lutre, Luteri, Lutherstraße and Лютерская ул.).