Where does “kohovalikko” come from?

kohovalikko (Finnish) comes from Finnish välikkö, from Finnish -ikko, from Proto-Finnic -ikko, from Proto-Finnic -i- — Plural number marker in other cases than the nominative (and optionally the genitive).

Ancestry of “kohovalikko”, step by step

Step	Language	Word	Meaning
1	Finnish	välikkö	passage
2	Finnish	-ikko	Forms nouns for groups of a particular number,...
3	Proto-Finnic	-ikko	Forms nouns indicating a group of things
4	Proto-Finnic	-i-	Plural number marker in other cases than the nominative (and optionally the genitive)

Every word from Proto-Finnic -i- →Every word from Finnish -ikko →Every word from Proto-Finnic -ikko →