Senses of Polysemous Nouns: Building a Computational Lexicon of Basic Japanese Nouns

We have constructed the IPA Lexicon of Basic Japanese Nouns (IPAL-BN), which has a hierarchical structure based on the syntactic and semantic properties of no,ms. In our lexicon, each lexical entry consists of subentries, and subentries have semantic property information. Among these elements, we focus here on the subentry description. Conventional Japanese dictionaries only enmnerate various usages. But it is also important to clarify the semantic relations between subentries. Thus we have developed a method for specifying the kind of relationship between subentries, using special cognitiw~ devices such as metaphor, metonymy, and synecdoche. After a brief review of the structure of our lexicon, we discuss how the nlethod can be applied to the lexical description. 1 I n t r o d u c t i o n Tile Information-technology Promotion Agency (IPA) i has compiled the IPA Lexicon of the Japanese Language for Computers, Basic Japanese Verbs (IPAL-BV) (1987) and Basic Japanese Adjectives (IPAL-BA) (1990). The IPAL-BV contains 861 verbs and the IPAL-BA contains 136 adjectives a~s lexical entries. These lexicons are available for public use and have been widely used in various mfiversity and research institute projects that have yielded encouraging results. We started work on the IPAL-BN project in 1990. hi May 1996, we released tlie third edition of tile IPAL-BN, with 1,081 nouns as lexical entries, for the public on networks with F T P service. The IPAL project is characterized by its linguistic basis. For example, the hierarchical structure i A special juridical body under the jurisdiction of the Ministry of International Tradc and Industry, Japmt. of the IPAL-BN, which consists of lexical entries, subentries, and semantic property information, reflects our linguistic considerations concerning the syntactic and semantic properties of nouns. Another example of benefits fi'om our linguistically inspired approach is the description of the kind of relationship between subentries. Such information would be useful in various applications, but is not yet explicitly provided in existing Japanese dictionaries. In the following sections, we first briefly introduce the general structure of the IPAL-BN, and then describe our method for specifying the kind of relationship between subentries. In the concluding renlarks, we also touch on implications of the nlethod for tile application systems. 2 S t r u c t u r e o f I P A L B N Figure 1 shows the top-level structure of the IPAL-BN. The H'AL-BN consists of 1,081 lexical entries.