Abstract
This paper examines the nature of filler speech in conversation by observing its five characteristics: untranslatability; unmistakability; essentiality/prohibitivity; capability of being "hopeless"; and privilegedness. Firstly, it is pointed out that no language's filler is rigidly translatable into other languages, which indicates that filler has a social as well as cognitive aspect. In order to integrate both aspects, we need a new socio-cognitive view of filler as a manifestation of the cognitive process the speaker is undergoing. The traditional view of conversational speech as an intentional act of transferring information cannot explain the facts of fillers, such as that fillers are inherently unmistakable for native speakers, that fillers look to be necessary/prohibited in accordance with situations, that fillers can be "hopeless," and that fillers can the privilege only of particular people of special status in the conversation.
