Where does “волнова́ться” come from?
волнова́ться (Russian) comes from Russian волнова́ть, from Russian волна́, from Old East Slavic вълна, from Proto-Slavic vь̀lna, from Proto-Balto-Slavic wílˀnāˀ, from Proto-Indo-European h₂wĺ̥h₁neh₂, from Proto-Indo-European -nós — Creates verbal adjectives from roots.
Ancestry of “волнова́ться”, step by step
Words derived from “волнова́ться”