Towards linking synonymous expressions of compound verbs to J apanese W ord N et (2019)

Abstract: This paper describes our project on Japanese compound verbs. Japanese “Verb (adnominal form) + Verb” compounds, which are treated as single verbs, frequently appear in daily communication. They are not sufficiently registered in Japanese dictionaries or thesauri. We are now compiling a list of the synonymous expressions of compound verbs in “compound verb lexicon” built by the National Institute of Japanese Language and Linguistics. We extracted synonymous words and phrases of compound verbs from five hundred million Japanese web corpora. As a result, synonymous expressions of 1800 compound verbs were obtained automatically among 2700 in the “compound verb lexicon”. From our data, we observed that some compound verbs represent not only motion but also additional nuances such as an emotional one. In order to reflect the abundant meanings that compound verbs own, we will try to think of a link of synonymous expressions to Japanese wordnet. Concretely, in the case of synonymous phrases, we try to link adverbial expressions which are a part of phrases to the adverbial synset in Japanese wordnet.

## introduction japanese "verb (adnominal form) + verb" compounds, which are treated as single verbs, frequently appear in daily communication, however, they are not sufficiently registered in japanese dictionaries or thesauri. the japanese "compound verb lexicon" was constructed by the national institute for japanese language and linguistics (ninjal) ( https://db4.ninjal.ac.jp/vvlexicon/ ). it has the meanings, example sentences, syntactic patterns and actual sentences from the corpus that they possess. however, it has no relation with another words, such as synonymous words and phrases. we detect them automatically as much as possible in order to help humans find out synonymous expressions that they may fail to bring to mind and then manually compile a lexicon of synonymous expressions of japanese compound verbs. in this paper, firstly we explain how to build the list of compound verbs and their synonymous words and phrases, and then consider what should be considered for linking to the japanese wordnet based on our obtained result. ## related researches so far, in nlp domain researches on complexed verbal meaning have treated multi word expressions in order to distinguish a literal meaning with the metaphoric meaning, but their purposes are word sense disambiguation or generation of compounding @xcite . in japanese, @xcite , and @xcite investigated ambiguities of compound verbs and tried to find the generation rules. as a resource on phrases, tanabe et.al (2014) built japanese dictionary of multi word expressions. however, works on the organization of words and phrases are few. our goal is to compile a list of words and verbal phrases with linking similar relations by using both automatic and manual ways. ## japanese compound verbs the morphological form of a compound verb is a combination of a first verb in an adnominal form and a second verb coming after it, as in hikari (adnominal form)-kagayaku (give.off.light & shine) 'shine like the sun', nage (adnominal form)-ireru (throw & put.in) 'throw in'. japanese compound verbs are divided into two types in terms of syntactic and morphological analysis; syntactic compound verbs and lexical compound verbs @xcite . @xcite says that syntactic compound verbs are easily recognizable and interpretable due to some characteristics, that is, a limitation of a variety of the second verbs, no restriction on the first verbs and so on. for example, "utai_hajimeru (sing & start, 'start singing'" "hanashi_hajimeru (speak & start, 'start speaking')" "hashiri_hajimeru (run & start, 'start running')" and so on. we can generate varieties of "verb_hajimeru (verb & start, 'start v_ing')". the second verbs of syntactic compound verbs are mainly aspectual verbs and also are limited to 30 verbs which are classified into 9 categories; inception, continuation, completion, incompletion, excessive action, habitual, reciprocal action and potential. we exclude the syntactic compound verbs and treat only lexical compounds which tightly combine two verbs as one word and not productive compared to syntactic compound verbs. ## result as a result, synonymous expressions for 1800 compound verbs were obtained automatically. the following is a result of " 持 ち 込 む (mochi_komu)" derived from pca. the synonymous expressions that we decided are surrounded with circles. sense 2: proceed though deadlocked, carry to one's advantage,… the list of synonymous expressions of "持ち込 む (mochikomu)" is as follows. sense1 : 運び入れる (hakobiireru, 'carry in') 搬入する (han'nyu_suru, 'carry to') 運び込む (hakobikomu, 'carry into') 運ぶ (hakobu, 'carry') 持って行く (motte_iku, 'take') 一緒に持っていく (isshoni motteiku, 'bring in', 'take … with [person]'.) sense2: もつれこむ (motsurekomu, 'to proceed though deadlocked') 優位に進める (yuui_ni (adj in adverbial form) susumeru, 'advance [the match]') 有利に運ぶ (yuuri_ni(adj in adverbial form) hakobu, 'carry to one's advantage') 引っ張り込む (hipparikomu, 'pull') 引き込む (hikikomu, 'pull') sense3: 取り込む (torikomu, 'incorporate') 取り入れる (toriireru, 'incorporate'), 導入する (dounyuusuru, 'introduce') ## japanese compound verbs and japanese wordnet we try to incorporate a synonym list that we compiled into japanese wordnet. currently, in japanese wordnet, 2584 compound verbs are registered. in our experiment, we obtained 1800 compound verbs. if those compound verbs and their synonymous expressions are registered, it would be useful for not only natural language processing like information retrieval, but also linguistic researches and language learning. our plan is: we show "持ち込む (mochikomu)" as an example in figure3. sense1 and sense3 are registered in japanese wordnet. sense2 is not registered. as for sense1, for the sake of a precise meaning of "持ち込む(mochikomu)", not only verb but also preposition "in", a kind of modifi-cation of a verb, is added and linked to the japanese wordnet. on the other hand, sense2 is a new meaning that we obtained from the data. the following expressions with underlines and those in boldfaces mean adverbial expressions which represent emotional nuance. we will link not only verbs like "proceed" "carry" "get through" and "win" but also a kind of modification for verbs like "through deadlocked" "advantage" "manage to" "tenaciously" to the japanese or english wordnet because they're important to understand a nuance of the compound verb "持ち込む (mochikomu)". as an example, one of synonymous expressions "粘り勝つ (nebarikatsu), 'compete tenaciously with each other and finally win' " are shown in figure 4 .  an inappropriate meaning sense1 sense3 粘り勝つ：nebarikatsu, 'compete tenaciously with each other, and finally win' 粘り(nebari(verb in adverbial form),'tenaciously' ) ←adverbial expression 勝つ (katsu, 'win') ← verb in predicative form figure 4. link of one of synonymous expressions of " 持 ち 込 む (mochikomu)": " 粘 り 勝 つ (nebarikatsu), 'compete tenaciously with each other and finally win' " ## conclusion in our work, first, we compiled a list of synonymous expressions of compound verbs by extracting from corpora semi-automatically and then try to link them to japanese wordent. japanese compound verbs have characteristics between words and phrases. we would like to consider how to combine phrasal expressions to wordnet. in addition, some compound verbs are deeply related with sense modalities. therefore, it would be important to treat the adverbial meaning which it implies. if we registered a link of not only words but also phrasal expressions, japanese wordnet would be useful for cross lingual works like linguistic researches, education and also, information retrieval.