From Proto-Indo-European *swer-.
*sъsora f
singular | dual | plural | |
---|---|---|---|
nominative | *sъsora | *sъsorě | *sъsory |
genitive | *sъsory | *sъsoru | *sъsorъ |
dative | *sъsorě | *sъsorama | *sъsoramъ |
accusative | *sъsorǫ | *sъsorě | *sъsory |
instrumental | *sъsorojǫ, *sъsorǫ** | *sъsorama | *sъsorami |
locative | *sъsorě | *sъsoru | *sъsorasъ, *sъsoraxъ* |
vocative | *sъsoro | *sъsorě | *sъsory |
* -asъ is the expected Balto-Slavic form but is found only in some Old Czech documents; -axъ is found everywhere else and is formed by analogy with other locative plurals in -xъ.
** The second form occurs in languages that contract early across /j/ (e.g. Czech), while the first form occurs in languages that do not (e.g. Russian).