In order to determine the extent to which lexical variation denotes the presence of regional boundaries, the current study examines the lexical variation across Brahui dialects in general and, in particular, the three main dialects of the Brahui language: Sarawani, Rakhshani, and Jhalawani. 20 Brahui variations were observed in this investigation. At the 10-word level, the words completely altered (melyparo/melypak/mellof, zeal/horhad/hor, hora/gade, razan/hozar, henak/hen/khary, bestry/lep/bherum, hasol/chat/besat, Tanya/chew, johan Lagery/dost barer/wharery, nary/rumbky/halmyky) and ten graphophonic alterations that affected sound and production (darasm/hrasam, dorogh/dhorogh, darakht/dharakch, yaka/yako, chaik/thaik, dangia/dangy/dary, chofot/thefarot, mahon/mahman, dhun/dhaun, hetiv/thive). The data was collected from 150 middle-aged participants (30 to 50 years old). The Social Identity Theory by Tajfel and Turner (1979) has been applied in this work. To measure the association between linguistic variables and social variables, the Chi-square test of independence was being used. According to the study, there is lexical diversity among the three Brahui dialects. Lexical diversity distinguishes residents of one region from those of another and can confirm the existence of regional boundaries.