A Corpus-based Syntactic Lexicon for Adverbs

A word class often neglected in the field of NLP resources, namely adverbs, has lately been described in a computational lexicon produced at CST as one of the results of a Ph.D.-project. The adverb lexicon, which is integrated in the Danish STO lexicon, gives detailed syntactic information on the type of modification and position, as well as on other syntactic properties of approx 800 Danish adverbs. One of the aims of the lexicon has been to establish a clear distinction between syntactic and semantic information-where other lexicons often generalize over the syntactic behavior of semantic classes of adverbs, every adverb is described with respect to its proper syntactic behavior in a text corpus, revealing very individual syntactic properties. Syntactic information on adverbs is needed in NLP systems generating text to ensure correct placing in the phrase they modify. Also in systems analyzing text, this information is needed in order to attach the adverbs to the right node in the syntactic parse trees. Within the field of linguistic research, several results can be deduced from the lexicon, e.g. knowledge of syntactic classes of Danish adverbs. lexicon for Danish adverbs has newly been produced as one of the results of a Ph.D.-project financed by the Nordic language technology research programme 2000-2004 (for more information see www.norfa.no). The lexicon is integrated in STO 1 which is a national Danish follow-up to the former EU-funded lexicon-projects PAROLE and SIMPLE (see http://www.ub.es/ gilcub/SIMPLE/simple.html#Language), and gives syntactic information on the type of modification and position as well as on several other syntactic lexical properties of approx 800 Danish adverbs, selected on the basis of their frequency in a text corpus. The lexical information is based on a series of syntactic tests as well as an individual examination of each adverb in a newspaper corpus of 30 mill. tokens (" Berlingske Aviskorpus " , Berlingske Tidende & Weekendavisen 1999). The lexicon, which can be used in NLP systems as well as for linguistic research, differs in several ways from earlier large-scaled computational adverb lexicons. First of all it is established by a corpus based study of the syntactic behavior of each adverb; secondly it focuses on properties which can be tested purely syntactically in order to keep a sharp distinction in the lexicon between syntax and semantics-semantic information on the adverbs is planned to be described afterwards at a semantic level in the STO lexicon, with links …