Basic Units of Lexicons and Ontologies: Words, Senses and Concepts

Basic Units of Lexicons and Ontologies: Words, Senses and Concepts∗∗∗∗ Hee-Rahk Chae Department of Linguistics and Cognitive Science, Hankuk University of Foreign Studies Wangsan-ri, Mohyeon-myeon, Yongin-si, Gyeonggi-do 449-791, Korea hrchae@hufs.ac.kr Abstract. Dictionaries and ontologies are very important resources not only for linguistic research and applications but also for other areas dealing with knowledge. In general, however, they fall short of our expectations. One reason for this under-expectation is that their basic units are not well-established. Dictionary head words have to be words rather than affixes or phrases. The meaning of a (head) word has to be carved into different senses on the basis of objective criteria. In addition, building blocks of ontologies have to be (simple and/or complex) concepts rather than senses. Keywords: Lexicons/Dictionaries, Ontologies, Head words, Senses, Concepts. ∗ This work was supported by a 2010 research grant from Hankuk University of Foreign Studies. Copyright 2010 by Hee-Rahk Chae. 1 Introduction Lexicons/Dictionaries have been one of the most important resources for linguistic research and applications. Ontologies are also becoming an indispensible resource not only for linguistics but also for other areas dealing with knowledge. In many cases, however, they fall short of our expectations. One reason for this under-expectation is that their basic units are not well- established. There are two kinds of basic units of dictionaries: head words and (word) senses. It is a truism that head words have to be words rather than affixes or phrases. However, it is not always true that only word units are registered as head words, especially in the dictionaries of agglutinative languages. In addition, the meaning of a word has to be carved into different senses on the basis of objective criteria. On the other hand, building blocks of ontologies have to be (simple and/or complex) concepts rather than senses. In section 2, we will evaluate the morpho-syntactic status of head words in a Korean dictionary. It will be shown that many head words are phrases and, hence, have to be removed from the list of head words. In addition, many elements that are treated as affixes are actually words and, hence, have to be registered as head words. We need to realize that agglutinative languages like Korean have many clitics, i.e. (syntactic) words which have some affixal properties as well. In section 3, we will consider issues related to polysemy. We need to distinguish between homophony and polysemy, on the one hand, and between polysemy and vagueness, on the other. Lastly, in section 4, we will consider basic units of ontologies. Some scholars argue that they have to be word senses rather than concepts. However, many scholars assume that they have to be concepts rather than senses. We will show, based on a variety of phenomena, that the building blocks of ontologies should be concepts. 2 The Morpho-syntactic Status of Dictionary Head Words Basic building blocks of dictionaries are their head words. It is rather simple to identify word units in such inflectional languages as English. However, the task is …

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