Where does “誰が” come from?

誰が (Japanese) comes from Japanese 誰, from Japanese が, from Finnish -nka — Forms nouns, mainly bird names (in dialects) and some toponyms.

Ancestry of “誰が”, step by step

StepLanguageWordMeaning
1Japanese誰"interrogative personal pronoun": who, whom
2JapaneseがIndicates the subject of a sentence; conjunction;...
3Finnish-nkaForms nouns, mainly bird names (in dialects) and some toponyms
Every word from Finnish -nka →Every word from Japanese が →Every word from Japanese 誰 →