Theodor Siebs
Theodor Siebs was a German linguist most remembered today as the author of Deutsche Bühnenaussprache, published in 1898. The work was largely responsible for setting the standard pronunciation of the modern German language and is referred to popularly by German speakers as der Siebs.
Siebs was born in Bremen, Germany on 26 August 1862. Siebs studied linguistics and classical philology in Tübingen and later was a professor both at the University of Greifswald and the University of Breslau. His writings on language and languages are varied, but there is an emphasis on the history and state of Frisian languages. His Deutsche Bühnenaussprache is still relevant, though, for practical purposes it has largely been supplanted by other works that employ the IPA, which Siebs' work did not.
Siebs died on 28 May 1941 in Breslau, Germany.