Modality and Modal Sense Representation in E-HowNet

136 Modality and Modal Sense Representation in E-HowNet* You-Shan Chung, Shu-Ling Huang, and Keh-Jiann Chen Institute of Information Science, Academia Sinica 128 Academia Road, Section 2, Nankang, Taipei 115, Taiwan {yschung, josieh, kchen}@iis.sinica.edu.tw Abstract. This paper explains how we define and represent modality in E-HowNet. Following Lyons (1977, reviewed in Hsieh 2003, among others), we hold that modals express a speaker’s opinion or attitude toward a proposition and hence have a pragmatic dimension and recognize five kinds of modal categories, i.e. epistemic, deontic, ability, volition and expectation modality. We then present a representational formalism that contains the three most basic components of modal meaning: modal category, positive or negative and strength. Such a formula can define not only modal words but also words that contain modal meanings and cope with co-compositions of modals and the negation construction. Keywords: modals, E-HowNet, negation 1. Introduction E-HowNet, which evolved from HowNet (Dong & Dong 2006), represents an effort to define our knowledge of concepts in the world. Unlike synonym-based frameworks (e.g. WordNet), E-HowNet defines a word by specifying the relationship, as indicated by a set of features, between a core concept to other concepts. Each concept can be further analyzed into atomic meaning units called sememes named after HowNet. Therefore, a word in E-HowNet can be defined with simple concepts, sememes, or a mixture of simple concepts and sememes interacting with features. E-HowNet has been proved to be capable of dealing with various kinds of concepts, even some very abstract ones, some of which being function words (Chen 2005 et al.) and the comparison construction (Huang et al. 2006), both describing the relationship between concepts. The representation of modality through E-HowNet is informative about the representational capacity of the framework for three reasons. First, modality is a meaning domain suggesting the attitude of the speaker and has a pragmatic dimension. Second, modality is considered a * This research was supported in part by the National Science Council under a Center Excellent Grant NSC 95-2752-E-001-001-PAE and Grant NSC95-2221-E-001-039. Copyright 2007 by You-Shan Chung, Shu-Ling Huang, and Keh-Jiann Chen 137 subcategory of function words that also has properties of content words (Chen 2005 et al.). The definition of modality thus provides insights into how words that fall somewhere in the middle on the content-function word continuum are defined. Third, modals’ co-occurrences with negation markers show discrepancies between surface structure and meaning, and serve as a on the content-function word continuum are defined. Third, modals’ co-occurrences with negation markers show discrepancies between surface structure and meaning, and serve as a testing ground for the defining capability of the framework. In E-HowNet, the word to be defined is assigned a head, which is semantically and syntactically similar to it. Then, words that describe the head are linked to the head through features. For example, the word 小子 xiaozi ‘lad’ refers to someone who is young. Therefore, we represent the word with the head 人 ren ‘person’ and the modifying word 年幼 nianyou ‘young’. Since 年幼 nianyou refers …

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