Two distinct stems that have been conflated into a single paradigm, as per Hakulinen; a case of suppletion.
The oblique stem *-ice- (sometimes reconstructed as *-icce-, which is probably secondary) is from Proto-Finno-Ugric *-ŋće, *-ńće, *-nće, *-nśe, and is cognate with Proto-Samic *-ńčë. The oblique stem is probably original. In many descendants the original nominative can be found in compounds, albeit in reduced form (*naic(ë)- > Estonian nais- in naissugu, Finnish nais- in naissuku, Ingrian nais- in naissuku, Karelian nais- in naispuoli, Livonian naiz- in naizjemā, Ludian naiž- in naižluad, Veps naiž- in naižvald, Votic naiz- in naizeläje). Remnants of the original nominative *-ici may be preserved in toponyms (Alhaisi near Salo in Finland, Ihalaisi, Ikäpäivösi and Vornaisi in Ingria).
The origin of the nominative *-inen is less clear; it might be related to *-na (diminutive suffix), in which case the -i- would be analogous to the oblique stem.
*-inën / *-inen (stem *-icë- / *-ice-)
Note: The Proto-Finnic declension system is yet to be reconstructed in detail. What is presented here is only one possibility. | |||
singular | plural | ||
---|---|---|---|
nominative | *-inën | *-icet | |
accusative | *-icen | *-icet | |
genitive | *-icen | *-ictën *-icidën | |
partitive | *-icta | *-icita | |
inessive | *-icessa *-icehna |
*-icissa *-icihna | |
elative | *-icesta | *-icista | |
illative | *-icesën | *-icisën | |
adessive | *-icella | *-icilla | |
ablative | *-icelta | *-icilta | |
allative | *-icelën *-icelëk |
*-icilën *-icilëk | |
essive | *-inna | *-icina | |
translative | *-iceksi | *-iciksi | |
instructive | *-icen | *-icin | |
comitative | *-innëk | *-icinëk | |
abessive | *-icetta | *-icitta |