Abstract This study investigates the emergent discourse marker (DM) nizhidao in Mandarin speech, focusing on its prosodic, positional, and pragmatic properties. While nizhidao has been broadly characterized as a marker of intersubjectivity, its functional versatility in real-time interaction, including marking shared knowledge, indexing/imposing new information, emphasizing content, and facilitating self-repair, remains less explored. Drawing on 38 telephone conversations, we propose a tripartite prosodic taxonomy to analyze its interactional behavior. Findings reveal that the pragmatic functions of nizhidao are systematically linked to distinct pitch contours and positional flexibility across turn-constructional units and turns. Despite lacking strict form–function mappings, prosodic features systematically predict its role in managing epistemic alignment and discourse coherence. Nizhidao exhibits emergent functional diversification progressing from propositional syntax to pragmatic periphery, characterized by increasing intersubjectivity and pragmatic conventionalization. This pragmatic conventionalization is marked by syntactic decategorization, phonetic reduction, and functional expansion, particularly at the right periphery. By integrating prosodic analysis with conversation structure, we challenge assumptions about the primacy of left-periphery subjectivity in Mandarin DMs and highlight the role of prosody in disentangling emergent versus stabilized DMs. Our results underscore the necessity for multimodal methodologies in accounting for the dynamic interplay of form, function, and position in pragmaticalization trajectories.
Shan et al. (Sun,) studied this question.