Raji is a Central Plateau (Iranic) language spoken in Kashan district, in the north-west corner of Esfahan Province, Iran. Here, we investigate the nature of Persian influence on the lexicon of two closely-related Raji dialects: that of Abuzeydabad, a desert outpost at 947m above sea level, and Barzok, a well-watered farming community at 2080m in mountains nearby. As expected, our analysis shows many inherited similarities due to linguistic relationship among the three Iranic varieties; cases of difference and innovation that distinguish them; and profound impact of Persian on both Raji dialects. Nonetheless, the degree and patterning of convergence with Persian is uneven, with the dialect of Abuzeydabad showing greater wholesale borrowing from Persian, as well as evidence of structural hybridization. To account for the divergent effects of Persian influence, we review social and geographic dynamics in the language contact situation. Key factors such as population, distance from the nearby Persian-speaking city of Kashan, language identity, and the impact of media and education are equivalent. However, a stark contrast between the towns’ geographic settings defines their social networks and patterns of mobility, and in turn how speakers of each linguistic code respond to Persian influence.