Study on Grammaticalization of Negation: From the viewpoints of Cognitive Linguistics and Linguistic Typology.

1. 日语和韩语中两种否定形式共存的研究：在韩语中，两种否定形式并存，而在日语中，只有一种否定形式，尽管在古日语中曾经有过一种否定形式。我们已经明确指出，这种差异源于两种语言的语义类型差异：韩语倾向于较少的歧义，而日语倾向于多功能性。由于这种差异，韩语中保留了较旧的否定句形式，与较新的否定句在功能上略有不同。另一方面，日本的旧的否定形式完全被新的否定形式所取代，这种否定形式比韩国的否定形式扮演着更多样化的角色。日本关西方言中两种否定形式共存的研究：与韩语相似，日本关西方言也有两种否定形式。他解释说，这两种语言的差异可以像韩国语一样，用符号原则来解释。否定与时间关系副词的相关性研究：我们阐明了时间关系副词的原意，如already和still会影响它们在否定句中的使用。那些源自具体概念（如空间）的概念不能出现在否定的范围内，而那些源自更抽象概念（如时间）的概念则可以。这种趋势在我们调查的四种语言中都是如此：日语、韩语、英语和德语。我们认为这是因为具体意义与否定的非实在意义是不相容的。这种现象体现了词根语素的原义对语法化过程的制约。

1. Study on coexistence of two forms of negation in Japanese and Korean: In Korean, two forms of sentence Negation coexist while in Japanese, there is only one form, although it once had another form in Old Japanese. We have made it clear that this difference is rooted in the Semantic Typological difference of the two languages: Korean tends toward less ambiguity and Japanese tends toward polyfunctionality. Because of the difference, the older form of sentence negation is preserved in Korean, with a slight functional difference from the newer one. On the other hand, Japanese older form of negation is completely displaced by the newer form, which plays more varied roles than that of Korean.2. Study on coexistence of two forms of negation in Kansai Dialect of Japanese: Similar to Korean, Kansai dialect of Japanese has two forms of negation. Be have explicated that the difference of the two forms can be explained based on iconic principles as in the case of Korean.3. Study on correlation between negation and time-relationship adverbs: We have explicated that original meanings of time-relationship adverbs, such as already and still affect whether they can be used in negative sentence. Those originated from concrete concepts such as space cannot occur in the scope of negation while those originated from more abstract concepts such as time can. This tendency is true of all the four languages we have investigated: Japanese, Korean, English, and German. We argued that this is because concrete meaning is incompatible with irrealis meaning of negation. This phenomenon exemplifies the case where the process of grammaticalization is constrained by the original meaning of the root morpheme.