This study examines the multifunctional nature of ēn’ēn 嗯嗯, a reduplicated pragmatic marker frequently used in Chinese social media communication. Based on an analysis of 5,750 instances from private WeChat conversations and interview data from sixteen participants, we identify eight functions that 嗯嗯 performs that differ from its single form 嗯: upgrading, mitigating, inviting elaboration, marking irony, pivoting topics, consolidating responses, maintaining continuity, and signaling closure. These functions operate simultaneously across two interconnected levels — interpersonal meaning management and conversational structure organization. Distributional analysis reveals that 嗯嗯 occurs disproportionately in high-power-gap and high-social-distance contexts, reflecting what participants described as “politeness anxiety” in asynchronous messaging. Our findings demonstrate that reduplication creates — rather than merely intensifies — pragmatic functions, offering new perspectives on conventional backchanneling frameworks. This study contributes to digital pragmatics by showing how morphological resources are repurposed to meet the interactional demands of text-based communication.