Linguistics Encyclopedia.pdf

A-Z 67
The system can be made to cope with garden-path type ambiguity (see
PSYCHOLINGUISTICS, pp. 370–1) by trying successive analyses of the problematic
structure until one is found which the context allows. Thus, had the input sentence been
The old train the young, the processor would have attempted the noun-phrase analysis of
the old train first, but would have reached a dead end at state S1, when the current word is
the while the arc demands that the current word be a verb. In such a situation, the
processor must backtrack over the input and arcs taken previously trying alternative arcs
at each state. In the case of The old train the young, when the backtracking process
reaches state NP1 old can be recognized as a noun on arc 7, and the rest of the analysis
follows straightforwardly (Wanner and Maratsos, 1978, p. 128). If such an approach is
persistently adopted, a separate sequence of arcs is required for each sentence type that
displays grammatical functions in different arrangements.
The ATN can, however, be given the power to alter a function label on any given
element if subsequent context demands it, so that when faced with a sentence in the
passive voice, for example, it may alter the label SUBJECT, which it has given to the
initial noun phrase, to OBJECT after it has recognized passive voice. This recognition
can be accomplished by adding CAT V arcs, which test for the presence of be and a past
participle ending on the main verb.
Finally, an ATN can postpone a decision about the grammatical function of a
problematic item by tagging it with HOLD. Elements in the HOLD list can be
RETRIEVEd and assigned a function later in the analysis, when there is enough context
to determine what the function should be (ibid. pp. 130–1). The HOLD list is particularly
useful during the processing of relative clauses because it allows the ATN grammar to
represent relative-clause patterns as systematic deformations of declarative-clause
patterns. This strategy captures a grammatical generalization about the structural
similarities between declarative and relative clauses (ibid., p. 137).
Wanner and Maratsos (1978, pp. 132–7) show how the grammar outlined above can
be extended to handle restrictive, unreduced, non-extraposed relative clauses, that is,
clauses which immediately follow and modify a head noun by limiting the range of
possible entities it can refer to (restrictive), which are introduced by a relative pronoun
(unreduced) and which are structurally identical to independent declarative clauses
(non-extraposed) except that one element is missing. Wanner and Maratsos (1978, p.
132) give the following examples (head noun phrases in italics, the gap where an element
is missing indicated by———):
…the girl who———talked to the teacher about the problem…
…the teacher whom the girl talked to———about the problem…
…the problem that the girl talked to the teacher about———…
As these examples demonstrate, the function fulfilled by the head noun is the same as the
function which would have been fulfilled at the gap had the relative clause been an
independent declarative clause:
The girl talked to the teacher about the problem
The girl talked to the teacher about the problem
The girl talked to the teacher about the problem