A Cognitive and Functional Linguistic Study on Directionality of Diachronic Changes in Grammatical and Lexical Structures Focusing on Japanese and Korean.

本研究的目的是找出日语和韩语在语法和词汇结构发展过程中的差异。在情态助动词方面，我们发现，尽管英语及其相关语言中的情态助动词表现出从道义意义到认识意义的发展，但在日语和韩语中却没有同样的方向性。事实上，认识义在古日语情态助动词中似乎一直占主导地位，并在发展过程中被消除了歧义。韩国人也是如此。我们认为，这种发展方向上的差异源于情态助动词来源范畴的差异。在否定方面，我们发现，韩国语的间接否定是沿着Jespersen的循环发展的，而日语的间接否定则没有这种循环发展模式。这是由于句子修饰语来源类别的差异造成的。韩国语中加入了状语成分，其位置更容易受到功能因素的影响。另一方面，由于日语的否定词本来是谓语，而日语是严格的动词词尾，所以它不太可能按照Jespersen的循环发生位置或角色的变化。最后，我们指出，mada在日语和英语中的语义延伸是不同的，这种差异是由原词所表达的意义类型的差异造成的。我们还发现，这种差异不仅可以解释日语和英语中的各种时间关系副词系统，也可以解释韩语和德语中的各种时间关系副词系统。

The purpose of this study was to find out regularities in the development of grammatical and lexical structures with special reference to Japanese and Korean. We mainly focused on modal auxiliaries, negation, and continuative aspect adverbs.On modal auxiliaries, we have found that although modal auxiliaries in English and its related languages show developments from deontic to epistemic senses, we cannot find the same directionality in Japanese and Korean. In fact epistemic meanings seem to have been predominant in modal auxiliaries in Old Japanese and they became disambiguated in the course of development. The same is arguably true of Korean. We argued that such difference in directionality of development derives from the difference in source categories of modal auxiliaries. We also argued that cultural-typological factor may also be involved in the disambiguation patterns in Japanese and Korean modal auxiliaries.As for negation, we have shown that while Korean sentential negation developed along the line of Jespersen's cycle, Japanese sentential negation does not show the similar cyclic pattern of development. This is due to the difference in source categories of sentence negators. As Korean recruited an adverbial element, its position is more likely to be affected by functional considerations. On the other hand, as Japanese negator was originally a predicate and Japanese language is rigidly verb-final, it was very unlikely to undergo change of positions or roles according to Jespersen's cycle.Finally, we have pointed out that semantic extension of mada in Japanese and still in English is different and this difference is caused by the difference in the type of meaning original words express. We have also shown that this difference can explain a variety of time-relationship adverb systems not only in Japanese and English, but also in Korean and German.