-itse

Etymology
From, consisting of the suffix plus an additional consonant. The additional consonant is only found in Finnish; the other Finnic languages have forms deriving from the vowel-final form. Cognate with 🇨🇬, 🇨🇬, 🇨🇬.

Suffix

 * 1) by, through;

Usage notes
Although commonly analysed synchronically as added onto the plural stem of the word, in origin the suffix simply began with  (like ), and no plural stem was involved.

Most grammars treat the prolative not as a separate case because it seems not to occur in concorded form (an adjective in PROLATIVE + a noun in PROLATIVE ); allegedly only with nouns in this form (e.g. ; ; etc.). However, there is one example which makes the prolative pass the concord test and therefore make the PROLATIVE a case:

Despite this, the prolative is widely held to be an adverbial case, not a proper case.