A dialect survey of the transition between two major Indo-Aryan languages in Nepal, Bhojpuri and Maithili, was conducted focusing on both the linguistic and sociolinguistic aspects of the various languages and dialects. The purpose of the study was to find out where and how this transition occurred between the pure Bhojpuri-speaking area and the pure Maithili-speaking area by surveying the area in between. To gather linguistic data, lists were elicited, and a sociolinguistic questionnaire, involving tape recording and oral questioning, was administered. It is concluded that caste dialects do not have an influence on the dialect transition of this survey area, but there is evidence that social-patterning dialects exist. This means that certain groups of people have certain social patterns in common and that there is more social interaction within this group than between groups. These social-pattern groups may or may not correspond to castes. The likeness percentages and the sociolinguistic scale table both showed that the transition is mainly a gradual, geographical transition from west to east, from Bhojpuri to Maithili. (NCR)