Maintaining ethnic identity amid additive multilingualism: language attitudes and ethnolinguistic vitality among the Hmong of northern Vietnam.

Research traditions in language attrition tend to read a minority mother tongue's retreat from public domains as a sign of one-directional decline. This study examines that equation through the case of the Hmong in northern Vietnam, where Vietnamese dominates public institutions while Hmong contracts toward family and community, and asks whether such a retreat is necessarily subtractive. The study draws on a qualitative, reflexive thematic analysis of semi-structured interviews with six Hmong speakers across three generations, with two comparison participants offering outsider and institutional perspectives. It is framed by social identity theory, ethnolinguistic identity theory, and the perceived ethnolinguistic vitality tradition. Findings reveal a clear domain-based functional differentiation: Hmong is anchored as the first-choice language in family and ritual domains, Vietnamese dominates public-institutional domains, and the two coexist in flexible bilingual practice in intermediate domains such as markets and social media. Across generations, affective loyalty to Hmong remains stable and unmarked, even as instrumental reasoning tilts toward Vietnamese among the young. Hmong speakers' perceived vitality forms a distinctive configuration-high cultural-status perception, low institutional-support perception, and demographic optimism-that decouples from objective institutional conditions. Contrasted with the deeper language shift documented among the Miao of Guizhou, China, this case shows that ethnolinguistic vitality is determined not by ethnic membership itself but jointly by institutional environment, demographic ecology, and community networks. The retreat of Hmong thus represents an additive multilingual configuration, marking the boundary conditions under which the attrition narrative holds and offering an empirical record of identity-driven language maintenance.