This study explores the speech level shifts from non-honorific to honorific situation by analyzing Korean spoken corpora of conversations between native speakers of Korean through a discourse-analytic framework. Although non-honorific styles (e.g., panmal) are used as frequently as honorific ones (e.g., contaysmal), little attention has been paid to non-honorific expressions in Korean, let alone to the speech level shift between non-honorific and honorific. Analyzing interactions between native speakers of Korean revealed that, depending on the change of their stance in response to the interlocutor’s utterance, speakers dynamically switched their speech levels not only within the boundary of non-honorifics or honorifics, but also across the dichotomous categories, that is, they changed from non-honorific to honorific speech styles. In general, speakers employed the speech level elevation from non-honorific to honorific when indexing a confrontational stance toward a topic and an object, or when upgrading an epistemic stance in naturally occurring interactions. The findings of this study encourage researchers to actively construct and use corpora of authentic/naturalistic conversations to explore the dynamicity of the speech level shift and its functions, which in turn contributes to developing instruction materials that reflect the dynamicity of the Korean honorific system.