The Reb gong Vale is a densely populated high-altitude agricultural oasis that runs north-to-south for approximately twenty kilometers through the north-eastern Tibetan Plateau, surrounded by barren pastoral hills that rise to rocky snow-capped peaks. The majority of the vale’s residents self-identify as Tibetan,but this population contains considerable diversity along religious, sectarian, and linguistic lines. We explore how the linguistic diversity of the region might have been maintained despite communities sharing a common identity, being engaged in inter-communal ritual networks, sharing common trade and pilgrimage sites,and living in close proximity in the absence of geographical barriers. Given their contiguity and interconnectedness, what enabled certain communities to remain distinct from nearby populations? Under such circumstances, how did relatively small communities maintain distinct languages? What prevented them from being linguistically assimilated?