[2] He received a degree in Slavic studies at the Faculty of Arts in Ljubljana and Prague, and a PhD in 1939 with a dissertation on Slovene phonetics titles Oris slovenskega knjižnega izgovora (A Description of Standard Slovene Pronunciation).

[1] Bezlaj published the founding work of Slovene onomastics Slovenska vodna imena (Slovenian Hydronyms; vol.

[2] His lifetime achievement is Etimološki slovar slovenskega jezika (Slovene Etymological Dictionary, 4 vols., 1976–2005), which was supplemented and edited after his death by Marko Snoj and Metka Furlan.

He discovered numerous parallels in various areas of Slavic territory by studying lexical elements in Slovene and Serbo-Croatian, pointing out traces of various linguistically heterogeneous strata reflecting older and younger Proto-Slavic migrations waves.

[1] His lifetime opus includes 260 bibliographic units, in addition to scientific discussions and articles, seven books and several study manuals.