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The clause-final verbal clusters in Dutch and German (and in general, in West Germanic languages) have been studied extensively in different syntactic theories. Standard Dutch prefers crossed dependencies (between verbs and their arguments) while Standard German prefers nested dependencies. Recently Bach, Brown, and Marslen-Wilson (1986) have investigated the consequences of these differences between Dutch and German for the processing complexity of sentences, containing either crossed or nested dependencies. Stated very simply, their results show that Dutch is 'easier' than German, thus showing that the push-down automaton (PDA) cannot be the universal basis for the human parsing mechanism. They provide an explanation for the inadequacy of PDA in terms of the kinds of partial interpretations the dependencies allow the listener to construct. Motivated by their results and their discussion of these results we introduce a principle of partial interpretation (PPI) and present an automaton, embedded push-down automaton (EPDA), which permits processing of crossed and nested dependencies consistent with PPI. We show that there are appropriate complexity measures (motivated by the discussion in Bach, Brown, and Marslen-Wilson (1986)) according to which the processing of crossed dependencies is easier than the processing of nested dependencies. We also discuss a case of mixed dependencies. This EPDA characterization of the processing of crossed and nested dependencies is significant because EPDAs are known to be exactly equivalent to Tree Adjoining Grammars (TAG), which are also capable of providing a linguistically motivated analysis for the crossed dependencies of Dutch (Kroch and Santorini 1988). This significance is further enhanced by the fact that two other grammatical formalisms, (Head Grammars (Pollard, 1984) and Combinatory Grammars (Steedman, 1987)), also capable of providing analysis for crossed dependencies of Dutch, have been shown recently to be equivalent to TAGS in their generative power. We have also discussed briefly some issues concerning the EPDAs and their associated grammars, and the relationship between these associated grammars and the corresponding 'linguistic' grammars.
Aravind K. Joshi, "Processing Crossed and Nested Dependencies: An Automaton Perspective on the Psycholinguistic Results", . September 1989.
Date Posted: 18 September 2007