The Syntactic Regularity of English Noun Phrases

THE SYNTACTIC REGULARITY OF ENGLISH NOUN PHRASES Lita Taylor, Claire Grover, Ted Briscoe ~ Department of Linguistics University of Lancaster Ballrigg Lanes., LA1 4YT, UK. ABSTRACT Approximately, 10,000 naturally occurring noun phrases taken from the LOB corpus were used firstly, to evaluate the NP component of the Alvey ANLT grammar (Grover et al., 1987, 1989) and secondly, to retest Sampson's (1987a) claim that this data provide evidence for the lack of a clear-cut distinction between grammatical and 'deviant' examples. The examples were sorted and classified on the basis of the lexical and syntactic analysis undertaken as part of the LOB corpus project (Sampson, 1987b). Tokens of each resulting type were parsed using the ANLT grammar and the results analysed to determine the success rate of the parses and the generality of the rules employed. INTRODUCTION In this paper, we present the results of an analysis of just over 10,000 English noun phrases (NPs) extracted from the Lancaster Oslo/Bergen (LOB) corpus treebank (Sampson, 1987b), a syntactically analysed 50,000 word subset of the 1 million word LOB corpus. The motivation for this research is twofold. Firstly, we wish to use this substantial data-base of naturally occurring constructions to test the accuracy mad adequacy of a (purportedly) wide-coverage sentence grammar (Grover et al., 1987, 1989) which has been developed over the past three years as part of a general-purpose morphological and syntactic analyser for English (hereafter the Alvey Natural Language Tools (ANLT) grammar). 2 The research reported here forms part of an ongoing project to evaluate the complete grammar using data extracted from the LOB corpus (see Briscoe et al., 1987a). Secondly, Sampson (1987a) has analysed a large subset of the same NPs and argued that they provide evidence against any clear-cut distinction between grammatical and 'deviant' sentences in natural language. Sampson suggests that the lack of such a distinction precludes the possibility of successful automated natural language processing (NLP) using a generative grammar. If correct, this conclusion would have profound implications for our own work and the majority of other work in NLP (since the ANLT grammar is a type of generative grammar). Therefore, we wished to assess the evidence which Sampson uses to sutrtx~ his conclusion. The LOB treebank is a manually analysed set of sentences drawn from the lexically analysed and tagged LOB corpus. ~ An analysis consists of a labelled bracketing containing lexical syntactic tags and phrasal or clausal 'hypertags'. Sampson (1987,'221) reports that there are 47 tags and hypertags relevant to the analysis of NPs - 28 lexical tags, 14 hypertags and 5 punctuation tags~ Analyses are assigned to sentences according to the intuitions of the linguist guided by a 'casebook' of precedents (Sampson, 1987b). One important feature of these analyses is that the resulting tree structures are quite 'shallow' in the sense that there are rarely intervening nodes between the topmost node marked NP and the lexical tags themselves. Whilst most NP postmodifiers are treated as independent constituents, NP premodifiers are largely analysed as immediate daughters of …

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