In this paper, we define and exemplify Late Vernacular Production (LVP), an under-researched pattern of language acquisition, socialisation, and use. LVP occurs in some minority communities where bilingualism in the local vernacular and the lingua franca is the norm: counter-intuitively, speakers with LVP are active users of only the lingua franca in childhood, going on to become active users of both the vernacular and the lingua franca in late adolescence or early adulthood. After distinguishing LVP from similar patterns of language acquisition and use — simultaneous and sequential bilingual acquisition, heritage language use, and language shift — we exemplify LVP with a case study from Abui (Timor-Alor-Pantar language family), spoken in east Indonesia. We follow this with results from an exhaustive survey of Island Southeast Asia and the Pacific, where we find a total of 32 attestations of LVP. Based on these attestations, we identify the factors that seem necessary for LVP to develop: a particular constellation of attitudes and ideologies which (i) identify the lingua franca as the language of opportunity, (ii) identify the local vernacular as the language of ethnolinguistic expression, and (iii) associate vernacular production with community integration upon reaching late adolescence/early adulthood. Finally, we discuss some of the broader theoretical implications of LVP — specifically, the challenge that LVP poses to current models of bilingual acquisition and use; the potential impact of LVP on contact-induced change; and the significance of LVP for models of endangerment, and by extension also for the design of documentation and revitalisation programmes.
