411 REFERENCE · Wiktionary
-oi-
Reference material by Wiktionary contributors. This retains its source identity and is not 411 news reporting.
Finnish
Etymology
The -i- has labialized the preceding -a- (initially only for back vowels, but the suffix has been later generalized for front vowels as well).
Interfix
öi
fi -i- plural marker plural
fi kasassa - kasoissa in the pile - in the piles 1
Usage notes
if the plural indicator is between two vowels it becomes fi -oj-
fi kasan - kasojen of the pile - of the piles 1