Proto-Slavic *kvasъ

→ Old Church Slavonic квасъ (inherited)

→ Lower Sorbian kwas (inherited)

→ Finnish kvassi (derived)

→ Hungarian kovász (derived)

→ Macedonian квас (inherited)

→ Macedonian квасец (inherited)

→ Polish kwas (inherited)

→ Romanian Covasna (derived)

→ Romanian covăsi (mention)

→ Russian квас (inherited)

→ Serbo-Croatian kvasac (inherited)

→ Serbo-Croatian квасац (inherited)

→ Slovak kvas (inherited)

→ Slovene kvas (inherited)

→ Albanian kos (derived)

→ Old Armenian քացախ (cognate)