want to go beyond this to ask: do the principles of the competence theory bear any resemblance to the principles that
thelanguageuser actuallyemploysinspeaking and understandinglanguage?Ifnot,itisnotentirelyclear exactlywhatis
claimed in attributing psychological reality to the competence grammar.
The parallelconstraint-based architecture developed in the past twochapters in fact affords a rather close relation to a
theory of processing. To review its overall character: Linguistic structure is viewed as a collection of independent but
linked levels of structure: phonology, syntax, and semantics. Each level of structure is characterized by its own set of
primitives and combinatorial principles. The linking among levels of structure is established by sets of interface
constraints—among which are the words of the language. Thus a well-formed sentence has well-formed structures in
each component,connectedina well-formed fashion bylinkingconstraints. Within thisorganization, syntax is but one
among several“cooperating”generative components.
The parallel constraint-based architecture is logicallynon-directional: one can start with any piece of structure in any
component and pass along logical pathways provided by the constraints to construct a coherent larger structure
around it.For example,onecan start witha piece ofphonology and, via theinterfaces, constructcorrespondingsyntax
and semantics; or one can start with a piece of semantics and via the interfaces construct corresponding syntax and
phonology. Because the grammar is logically non-directional, it is not inherently biased toward either perception or
production-unlike the syntactocentric architecture, which is inherently biased against both!^96
But we can go farther. It is possible to construct a model of processing whose components correspond directlyto the
components in the parallel model:
- Corresponding to the formation rules and constraints internal to a particular level of structure are processes
which, given a collection of fragmentary structures in a particular format, attempt to construct a fully
specified structure in that format. The classic example is a syntactic parser, which is given a sequence of
lexical categories like (1a) and constructs a fully specified syntactic structure like (1b).
(1) a. Determiner + Adjective + Noun + Auxiliary + Verb + Noun
b. [S[NPDet [APA] N] Aux [VPV[NPN]]]
Let us call such a process anintegrativeprocess. For each set of formation rules that defines a level of linguistic
structure, the language processor requires an integrative process that uses these principles to construct structures at
that level.
- Corresponding to interface constraints are processes that use one for mof linguistic structure to create
another. The classic example is the conversion of
198 ARCHITECTURAL FOUNDATIONS
(^96) A parallel argument is made for HPSG by Pollard and Sag (1994).