Case roles, according to the work by Fillmore (1967), are the semantic roles of noun phrases in relation to the syntactic structures that contain these noun phrases. The term case role is most widely used for purely semantic relations, including theta roles and thematic roles, that can be independent of the morpho-syntax. The concept of case roles is related to the larger notion of Case (with a capital letter C) which is defined as a system of marking dependent nouns for the type of semantic or syntactic relationship they bear to their heads. Case traditionally refers to inflectional marking.
The relationships between nouns and their containing structures is one of both syntactic and semantic value. The syntactic positional relationships between forms in sentences varies cross-linguistically and allows grammarians to observe semantic values in these nouns by examining their syntactic values. Using these semantic values gives the base for considering case role in a specific language.
Case theory includes, in addition to its inventory of structural cases, a series of lexical cases that are assigned at deep-structure in conjunction with theta role assignment. In addition to its relation to Case (case based on syntactic structures), these semantic notions of case role are closely related to morphological case as well.
Inventory of case roles
The following list of case roles are frequently distinguished in literature, but are by no means an exhaustive list since there is no consensus on the universal inventory of roles, nor a universal agreement as to the correct assignment of constituents to roles.
Early contributions to case role
Roman Jakobson's work on Case Role in Russian
In his article on the case system of Russian, Roman Jakobson (1958) closely examines case assignment and argues for a feature decomposition of case on the basis of semantic considerations. Jakobson (1958) proposed a 3-feature binary case system for Russian case which includes the following: [±marginal, ±quantifying, ±ascriptive] (where the negative value is considered to be unmarked). The term 'marginal', distinguishes the direct and non-direct cases. Only the [-Marginal] cases may occur in subject and object position. 'Quantifying' indicates the relevance of the extent to which the noun is a participant in the event. 'Ascriptive' puts emphasis on directionality.
Jakobson considers case to be bundles of these three features which can be assigned to morphological cases in the following way:
He uses these decomposed case features to account for the case alternations in subject and object position. Additionally, he also argues for how there should be a universal inventory of case roles. Fillmore's work (1968) on case role closely follows up on these ideas and contributions by Jakobson.
Multiple case roles
There is a theory that multiple case roles can be assigned to noun phrases. The reasons for having more than one case role is due to the differences in the sentences’ semantic effects. Bhat (1997) proposed that the speaker of a language would have the option of assigning any single case role out of the multiple case role alternations available in a given context. This is not done by a transformational rule, but due to the deep structure representations (the core semantic relations of the sentence).
Examples
(1a) || John sprayed the wall with paint. (1b) ||John sprayed paint on the wall.
In comparing sentences (1a) and (1b), it demonstrates that the surface structure representation for each sentence (the structure following the phonological form of the sentence) is different. However, in order to account for the meaning distinctions that exist in (1a) and (1b), it has been demonstrated that these distinctions are due to the differences in the deep structures of each sentence and can be resolved by assigning a different case role to the NP. With "paint" acting as an instrument, and "the wall" being the location, sentence (1a) might infer that all the paint was used, but that not necessarily all the wall was covered. Sentence (1b) might imply that the whole wall is covered, but that John did not use all the paint he had available to him. This analysis supports how NPs can have multiple case roles.