This study has investigated the interactional functions of the discourse marker - nikka in spoken Korean. When this marker is used at a sentence-final position, it exhibits non-referential meanings that play a significant role in verbal exchanges. Within discourse analysis, the study has examined how speakers express a particular attitude, through the use of this marker when quoting the speaker's own utterance. For a theoretical framework, the notion of 'involvement' has been used to describe the interactive nature of - nikka, by observing how the speakers use this marker to create interpersonal involvement in interaction. The current study reveals that, while this marker is used as a self-quotation in order to convey the speaker's own utterance as frequently used in casual conversations, - nikka displays different functions: hearer-oriented recollection, speaker-oriented recollection, and mutually understood recollection. By exploring these functions, this research sheds light towards understanding how the speaker's attitude is manifested through a particular discourse marker, and how that can have an influence on the hearer in interaction. Consequently, this is a clear demonstration of how language is not only a device to convey information or thoughts but also the speaker's expressive ('affective' or 'emotive') meanings. Furthermore, the findings in this study will contribute towards understanding particular functions of self-quotation in the Korean language.