Where does “raappiintua” come from?

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

Ancestry of “raappiintua”, step by step

Step	Language	Word	Meaning
1	Finnish	raappia	—
2	Finnish	-uttaa	aivastaa + API → aivastuttaa; rakentaa + API →...
3	Ingrian	-ua	Used to form inchoative verbs
4	Finnish	-ttää	Front vowel variant of -ttaa
5	Proto-Finnic	-ttadak	Creates causative verbs from regular verbs,...
6	Proto-Uralic	-kta-	—

Every word from Proto-Uralic -kta- →Every word from Finnish -ttää →Every word from Finnish -uttaa →