English Adverb Generation in Japanese to English Machine Translation

English Adverb Generation in Japanese to English Machine Translation Kentaro OGURA, Francis BOND and Satoru IKEHARA NTT Communication Science Laboratories 1-2356 Take, Yokosuka-shi, Kanagawa-ken, 238-03 JAPAN {ogura, bond, ±kehara}@nttkb. ntt. jp Abstract This paper proposes an English adverb ordering method based on adverb gram- matical functions (subjuncts, adjuncts, dis- juncts and conjuncts) and meanings (pro- cess, space, time etc.), preferred positions in sentences (initial, medial, end, pre, post), and priorities between adverbs with the same preferred position. 1 Introduction Adverbs I have various complex grammatical func- tions in sentences but they do not construct the main parts of sentence meaning. In natural language pro- cessing, therefore, the study of adverbs has not de- veloped very far to date. Linguists have examined adverb grammatical functions and meanings in detail(Quirk et al., 1985) (Greenbaum, 1969). Our method is based on these studies about adverb grammatical functions and meanings. Other adverb studies by linguists in- clude studies which handle the meanings of specific adverbs, such as "even ", "s~ill" and "already " and temporal adverb studies which handle temporal se- mantics in sentences. The main problems in adverb processing in Japanese to English machine translation(Ogura et al., 1993) are as follows: 1. the multiplicity of adverb meanings 2. differences in expression between Japanese and En- glish for adverbial meaning 3. word ordering of English adverbs in English gener- ation 4. representation of adverbs in a computer In this paper, we focus our attention on the 3rd problem. 2 Classification of English Adverbs 2.1 Position In our adverb position system for English adverb generation, 5 positions are provided. The first is initial position (IP), the beginning of the sentence. The second is medial position (MP), between the subject and predicate, or if auxiliary verbs are in- volved in the sentence just after the first auxiliary 1In this paper, adverbs include idiomatic adverbial phrase, such as "on purpose". verb. The third is end position (EP), after a predi- cate. Pre position (PreP) and post position (PostP) are provided for adverbs as modifiers. A pre posi- tion adverb comes before a modificant and a post position adverb comes after a modificant. 2.2 Classification Adverbs can roughly be divided into subjuncts, ad- juncts, disjuncts and conjuncts by their grammatical function. We classify adverbs by specifying differ- ences in meaning and preferred positions within sen- tences for each adverb. The classification is shown in Figure 1. Subjuncts Viewpoint, Courtesy, Subject-orientation Item General Volitional MP & EP Focusing Restrictive PreP & PostP, Additive PreP & PostP & EP & IP & MP, Emphasizers Prep & EP, Amplifiers PreP & PostP & EP, Downtoners PreP & EP, Adjuncts Manner, Means, Instrument, Position, Direction, Time-position MP & EP, Span MP & EP, Time-frequency Definite, Indefinite MP & EP Disjuncts Style, Content Value Judgment Non-subject, Subject, Degree of truth Conjuncts IP & EP Post Position Numeral Modifiers Figure 1: Adverb Classification 3 Word Ordering Method for English Adverbs Adverbs usually have many meanings, especially ad- verbs which are used frequently in our …

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