This article incorporates themes from ethnolinguistics, linguistic anthropology, sign linguistics, and decolonization of research methods. We examine a Yolŋu-led collaboration to save their endangered Yolŋu Sign Language (YSL) in Australia's remote North East Arnhem Land. YSL is an alternate bimodal language for hearing Yolŋu and the primary language of Deaf Yolŋu. In light of dissimilar worldviews between indigenous Yolŋu people and the Australian state, we describe opportunities for ethical research and equitable collaboration, with a practical guide to strategies of local action research. We deploy ethnographic insight to describe a globally rare and distinctive metaphysics of place and language. We find that long-term, embedded, place-based collaborative research, through local language, bestows a deeper understanding of Yolŋu spiritual connection to kin and country. Further, we found the affirmation of Yolŋu life space—as embodied in life on the homelands—provokes a different, empowered, non-subordinate cultural future. This embodied cultural future supports the critical intergenerational transmission of the Yolŋu ancestral inheritance, of kin and country, and its languages, signed and spoken, while resisting internal colonization.