From 1900 to 1907, he was in Leiden, then at the University of Leipzig where he studied Baltic and Slavic languages.
Under the supervision of August Leskien, he defended his thesis on Nature comparisons in Lithuanian songs and laments (Die Naturvergleiche in der Liedern und Totenklagen der Litauer [1][3]1907,[4] Lithuanian 1919, translated by M. Biržiška).
From 1946 to 1952, he was Full Professor of Baltic and Slavic languages at Leiden University.
[3] From 1912 to 1935, he edited the Dictionary of the Dutch Language (Woordenboek der Nederlandsche Taal).
[3][5][6] He published articles on Lithuanian onomastics and the Prussian language in the publications of the Dutch Academy of Sciences.