 He had a comprehensive knowledge of the Finno-Ugric languages, and he used this knowledge in his doctoral dissertation about the Hungarian possessive constructions such as "isten-adta" /god-given/ in Finno-Ugric languages in 1939.This work is the most detailed source of description of the prenominal relative clauses in Finno-Ugric languages, though he considered and analyzed this constructions as possessive constructions.He fought against the linguistic superstitions in Hungarian.