In many societies, dialectometry has revealed strong correlations between geographic distances and dialect differences (e.g., Gooskens, 2005; Heeringa & Nerbonne, 2001; Nerbonne, 2009, 2010). But what happens when dialectometry is applied to a small, clan-based society such as the indigenous Sui people of rural southwest China? The Sui results show a strong correlation between dialect difference and geographic distance, thus supporting Nerbonne and Kleiweg's (2007) Fundamental Dialectological Postulate. A new culturally specific computation, “rice paddy distance,” also provides a strong correlation with dialect differences. However, the study finds that some dialectometry patterns of larger societies are not “compressible” into small societies such as Sui. Clan exogamy also poses challenges for dialectometry. Nonetheless, the overall results show that basic principles of dialect variation in space can be generalized cross-culturally, even across very different cultures. This paper also suggests a “lower limit” for dialectology, that is, the smallest distance where regional dialectology may be relevant, all other things being equal.