The verb is often accorded a dominant role in the grammatical structuring of its clause, which it realizes principally via its argument structure. In one popular view of clause structure, a given verb's argument structure grammatically specifies how many nouns will accompany it, and which roles they will play, within the clause. From a cognitive point of view, an argument structure is nothing more than a structure of expectations triggered by a verb. Specifically, each use of a particular verb token raises the reliable expectation that a certain predictable configuration of nominal roles will occur in meaningful relation to it. The verb enjoy, for example, can be predicted to co-occur with a subject argument and an object argument, corresponding to the experiencer of enjoyment and the thing enjoyed, respectively.
The particular nominal roles and their configurations will vary from verb class to verb class. Though subject to certain qualifications (Goldberg, 1998), this account will suffice for present expository purposes.
Among the arguments of a verb, some are core (subject, direct object, indirect object) and some are not (obliques, such as locative or temporal adverbials). The core arguments tend to be those most central to the clause structure. They are highly grammaticized, which is to say, obligatory rather than optional and relatively bleached of specific semantic meaning. For Argument Structure it is the clause core that is the primary unit of analysis, that is, the verb with its core arguments. In general all clause core elements tend to fit within the unified intonation contour that demarcates a single intonation unit.
Referential Form
The noun phrase, considered as a structural position within a clause, can be realized by a wide variety of forms, such as a full lexical noun phrase with or without various modifiers, a personal pronoun, and so on. Grammarians would normally leave the selection among these realizations to factors outside the domain of syntax. Recognizing that discourse-pragmatic considerations such as referential continuity, information status, accessibility, and so on influence the choice of referential form (Smith, W. 1996, 163-189), nevertheless from a narrowly structural perspective the variation counts as optional.
