抄録
It has not been previously noticed that emotives (interjections) corresponding to speaker's changing his/her mind are often obligatory rather than optional in Japanese spontaneous communication. For example, in replying to a stranger's question "Is there any police station around here?" the speaker MUST utter the emotive "a" to reveal that s/he has hit upon the place of the police station between "saa" (well, in negative feeling) and "asoko-ni arimasu" (it's over there.) This paper examines when and how this obligation occurs and disappears by distinguishing two levels of knowledge (superficial 'acted' level vs. actual level), and claims that emotives of changing mind become obligatory in accordance with the gap between two consecutive speech acts, which is counted on both levels of knowledge. When the gap is too big, emotives are obligatory inserted between them to connect these speech acts smoothly.
