NULEX: An Open-License Broad Coverage Lexicon

Broad coverage lexicons for the English language have traditionally been handmade. This approach, while accurate, requires too much human labor. Furthermore, resources contain gaps in coverage, contain specific types of information, or are incompatible with other resources. We believe that the state of open-license technology is such that a comprehensive syntactic lexicon can be automatically compiled. This paper describes the creation of such a lexicon, NU-LEX, an open-license feature-based lexicon for general purpose parsing that combines WordNet, VerbNet, and Wiktionary and contains over 100,000 words. NU-LEX was integrated into a bottom up chart parser. We ran the parser through three sets of sentences, 50 sentences total, from the Simple English Wikipedia and compared its performance to the same parser using Comlex. Both parsers performed almost equally with NU-LEX finding all lex-items for 50% of the sentences and Comlex succeeding for 52%. Furthermore, NULEX’s shortcomings primarily fell into two categories, suggesting future research