A predicate is the pragmatic goal of a speech act; that is to say, a predicate is the reason why someone embarks on an act of predicating-and-referring in the first place. For the purpose of investigating linkage phenomena, clauses may be considered as expanded predicates, and grammatically equivalent to them. In Role-and-Reference grammar the clause is understood to be a layered structure, with an inner level called a nucleus, an intermediate level called a core and an outer layer called a periphery. The nucleus contains the non-finite manifestation of a lexical predicate — a denotative type in Langacker's (1991:51) terms. The core contains the nucleus and its ‘core arguments,’ which are nowhere well defined, but which are considered generally to be the subject and in transitive predicates one or two of its objects, selected on morphosyntactic grounds by access to a privileged position within the clause, and on semantic grounds by reference to a hierarchy of semantic roles (Foley & Van Valin 1984:59). The periphery contains everything outside the core. Also distinguished (ibid: 208) are two relevant categories in the clause, a substantive category called ‘constituents’ and a non-substantive one called ‘operators.’ The operators over a predicate are aspect, directionality, modality, reality status, tense, evidentiality and illocutionary force. These operators are said to have scope over (be an integral part of, make specific reference to) different layers of the clause.