Where does “haisua” come from?

haisua (Ingrian) comes from Ingrian -ua, from Finnish -ttää, from Proto-Finnic -ttadak, from Proto-Uralic -kta-.

Ancestry of “haisua”, step by step

StepLanguageWordMeaning
1Ingrian-uaUsed to form inchoative verbs
2Finnish-ttääFront vowel variant of -ttaa
3Proto-Finnic-ttadakCreates causative verbs from regular verbs,...
4Proto-Uralic-kta-—
Every word from Proto-Uralic -kta- →Every word from Finnish -ttää →Every word from Proto-Finnic -ttadak →