Fig. 5.6 Incorporating a grammatical function tier
This picture differs fro mthe usual LFG architecture in one i mportant respect: it retains so me direct connections
between syntax and conceptual structure. The idea is that the grammatical function tier provides a sort of
“supercharger”on the syntactic expression of semantic relations—a way to regulate more precisely the expression of
argument structure. But like tiers in phonology, it deals only withpartsof the structures it relates, ignoring the rest. In
this case the rest is all the periphery/cômeurs/obliques, plus matters such as the determiner and auxiliary systems.
These aspects of syntax and semantics are“invisible”to the interfaces that engage grammatical functions. Hence the
tier that deals with grammatical functions is not a“full”level (as in LFG and RG): rather it is a very limited little
“accountingsystem”that only has to push around a few pieces of structure. Presumablyitis thislimitedcharacter that
gives the syste mits relative efficiency and precision. It is an interesting challenge for future research to see whether a
grammatical-function tier of this limited sort can be crafted from the existing theories of grammatical functions, and
whether it yields any insight over current approaches. Whether or not this speculation works out, it is most natural to
explore it in the context of a parallel architecture.