By surface analysis, *pečenь + *-ьka.
*pečenьka f
singular | dual | plural | |
---|---|---|---|
nominative | *pečenьka | *pečenьcě | *pečenьky |
genitive | *pečenьky | *pečenьku | *pečenьkъ |
dative | *pečenьcě | *pečenьkama | *pečenьkamъ |
accusative | *pečenьkǫ | *pečenьcě | *pečenьky |
instrumental | *pečenьkojǫ, *pečenьkǫ** | *pečenьkama | *pečenьkami |
locative | *pečenьcě | *pečenьku | *pečenьkasъ, *pečenьkaxъ* |
vocative | *pečenьko | *pečenьcě | *pečenьky |
* -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).