Purpose: This study aims to explore the crucial role of language in constructing and expressing individual and group identities across diverse social and cultural contexts in Vietnam. This study integrates theoretical frameworks from Gee's work on discourse and identity, and Bucholtz and Hall's principles on the linguistic construction of identity. Methods: The study employs a mixed-methods approach combining ethnographic observations, in-depth interviews, and discourse analysis to gain deep insights into the complex interplay between linguistic practices and identity formation processes. Results: The key findings reveal that language serves as a powerful tool for constructing multifaceted identities, with linguistic choices functioning as identity markers, enabling the expression of group membership, the establishment of boundaries, and the negotiation of power relations within and across communities. These findings provide deep insights into understanding the role of language in shaping identities in Vietnam. Discussion: The study has practical applications in developing comprehensive, equitable, and culturally-sensitive language resources, educational strategies, and language policies to recognize and value the linguistic diversity of multilingual communities.