Why translation is not enough and how functional language use can improve cultural adaptation in bilingual implementation settings

Despite widespread bilingualism, most intervention adaptation efforts remain grounded in monolingual assumptions. This approach poorly reflects how bilingual communication functions. Research in sociolinguistics and psycholinguistics shows that bilingual speakers do not “turn off” one language when using another. Instead, both languages often remain co-activated and are flexibly deployed to shape meaning and emotion depending on language proficiency and context. When applied to clinical interventions and the implementation strategies that support them, monolingual adaptations that restrict content to a single language risk misaligning interventions with how bilingual communication and language processing actually operate. We propose three approaches to guide linguistic adaptation in interventions and the implementation strategies that support them: functional code-switching, translanguaging, and plurilingual design. Together, these approaches shift adaptation away from single-language translation toward intentional use of bilingual communication practices. Drawing on a case study, we illustrate how these practices can influence proximal processes that support engagement and change. Specifically, we propose that bilingual language practices can reduce linguistic friction and cognitive load, increase perceived fit and credibility by mirroring how bilingual individuals communicate, and strengthen relational safety through brief language practices into intervention design, delivery, and implementation research. In bilingual settings, language is not merely a channel for delivering the same content in different words; it actively shapes how information is interpreted, how strongly it resonates, and how connected individuals feel to the speaker or context. While monolingual approaches remain appropriate for monolingual communities, their routine application to bilingual contexts risks overlooking how flexible language use supports engagement and meaning-making. We therefore call for a functional model of linguistic adaptation in which language choice and switching are treated as intentional design elements that shape intervention processes, rather than as secondary stylistic modifications applied after content is finalized.