This paper examines three social development projects from the Republic of Vanuatu— the most linguistically diverse nation (on a per capita basis) in the world—that each seek to promote, support, and maintain vernacular languages. Vernacular or mother languages are widely recognised as crucial to the practice and transmission of intangible cultural heritage, as well as the continuance of biocultural diversity. Amidst substantive socio-cultural and economic change, linguistic diversity is shrinking. The locally embedded rationales behind the value of vernacular language usage in Vanuatu both echo and extend the most commonly listed attributes of vernacular language usage. In addition to nourishing cultural identity and expression, enhancing education outcomes and supporting human-environment well-being, the practitioners and participants involved in these three programs viewed vernacular language as not just a vehicle but a form of social capital itself that positively informs social order. These relatively low cost, home-grown approaches to local language maintenance, are an innovative and promising model for combating language shifts in Vanuatu, and perhaps elsewhere in Melanesia. They also raise interesting questions about who ultimately gets to define what does and does not constitute ‘social capital’, ‘governance’ and ‘cultural heritage’.