Sorbian Case Inventory (Upper and Lower) #
@cite{stone-1993-sorbian} @cite{blake-1994}
Per @cite{stone-1993-sorbian} (p. 614): "Upper Sorbian has seven cases (nominative, vocative, accusative, genitive, dative, instrumental and locative). Lower Sorbian, having lost the vocative, has only six cases. All the dialects have at least six cases. ... Even in Upper Sorbian it is only masculine nouns that have a separate vocative form (and only in the singular). There is one exception to this rule: USo. mać 'mother' has vocative singular maći."
Both varieties share the 6-case core (coreInventory); Upper Sorbian
adds a productive masc-sg VOC. The Lower Sorbian vocative is attested
"only in Jakubica's New Testament (1548)" — fossil only.
Stone (p. 614) also documents that "in both Upper and Lower Sorbian the independent, prepositionless function of the instrumental has been lost" — the marked Slavic INST-prepositional pattern (cf. Slovene per @cite{priestly-1993}; contrast with Russian @cite{timberlake-1993} and Cassubian @cite{stone-1993-cassubian} where bare predicative INST is robust).