casesforsubjectsand objectsrespectively, againirrespectiveofthematicrole (althoughthere are oftencertainsemantic
intrusions such as dative-marked subjects for Experiencers) (Maling et al. 1987).
One might also include in this system of grammatical functionsthe designated position at the front of a clause (“A-bar
position”or“Specifier of CP”in GB terminology) that is occupied by question words, relative pronouns, topics, and
the like. The semantic roles appearing in this position do not show an overwhelming commonality; they are certainly
rando min ter ms of the matic roles; they show a mixture of topic-focus roles and quantificational (variable-binding)
status. For convenience I'll call this position“syntactic topic,”while recognizing that this ter mdoes not do it justice.
That there is something special about subject, object, indirect object, and syntactic topic also emerges implicitly from
the fact that so many different theories of syntax are preoccupied with them. Within GB/MP, the“abstract case
module”deals with subjects, objects, and indirect objects; and a vast body of research beginning with Ross (1967) has
dealt with constraints on the relation between an occupant of syntactic topic position and its trace (the Sentential
Subject Constraint in section3.2.3 is an example). GB/MP singlesout these twoclasses of phenomena (plus anaphora
and quantification) as principal components of“core”grammar, while most other phenomena are relegated to the
“periphery.” Relational Grammar is almost entirely concerned with subject, object, and indirect object; other
arguments and adjuncts are called chôomeurs (‘unemployed’) and are inert within the system. Lexical-Functional
Grammar is founded on the argument that as wellas the syntactic levelof phrase structure, there is an additional level
that codifies grammatical functions—again stressing subjects, objects, and indirect objects and classifying everything
else in a relatively undifferentiated“oblique”category. And the Argument-Linking Hierarchy of the previous section
pertains specificallyto NP arguments—again, subjects, objects, and indirectobjects. The fact that all these frameworks
arrive at similar notions, though in entirely different terminology, cannot be a coincidence: something must really be
going on in language.
The most direct way to incorporate grammatical functions into the architecture is to adopt the proposal of Lexical-
Functional Grammar that, in present terms, there is an additional tier of syntactic structure that intervenes between
phrasal syntax and semantics. We might present the relevant part of the architecture as in Fig. 5.6.