Within the intellectual landscape of East Africa, an Omani jurist-occultist named Nāṣir b. Abī Nabhān al-Kharūṣī (1778-1847) engaged in a profound debate on the sentience of trees. Under the patronage of the Būsaʿīdī Sultan Saʿīd b. Sulṭān (r. 1804–1856), he embarked on a polymathic project to understand his new East African home. His legal and ontological inquiry of whether trees possessed vegetal souls and the ability to wield magical powers over humans, was part of a multidimensional intellectual project. In his pursuit, Nāṣir authored two groundbreaking works that sought to translate the Swahili Coast through two mediums: the occult sciences and the Swahili language. Well before European colonizers in the mid-nineteenth century endeavored to document the Swahili language and East Africa’s ethnobotanical knowledge, Nāṣir took the initiative. He authored the first Swahili dictionary and an original occult-scientific treatise, drawing insights from extensive fieldwork across the Swahili world and the Arabian Peninsula. His research gleaned knowledge from a diverse range of oral and textual sources, including both enslaved and free interlocutors. This Omani intellectual’s contributions marked a pivotal moment in Arabian knowledge of East Africa. In his methodological intervention, Nāṣir seamlessly united the nature and culture of East Africa. By integrating indigenous knowledge—both cultural and environmental—his approach aimed to make East Africa legible and accessible to the expanding Omani Empire and his Arabic readers across the Western Indian Ocean. In this presentation, I will delve into Nāṣir’s writings and their intellectual context to illustrate how his methodological intervention not only broke new ground in approaching Swahili as a language to learn and a language of learning, but also fundamentally contributed to the documentation of East Africa by integrating its indigenous cosmic and cultural knowledge into the expanding Omani Empire’s intellectual landscape in Arabia and East Africa.