The indo-aryan languages and dialects constitute a dialect continuum, characterised by variable, non - discrete boundaries between speech communities in order to reconstruct linguistic history it is necessary to take stock of this sociolinguistic context and adjust the methods of reconstruction accordingly this study presents a theoretically robust, sociolinguistic framework for historical reconstruction which supplements a traditional comparative reconstruction of phonology and morphology the language varieties examined in this book are known by a number of names including kamta, rajbanshi, or simply the deshi bhasha of north bengal and west assam this study provides evidence for a protolanguage, termed proto kamta (c ad 13 - 16 century), which was the point of common origin for these lects, and defines them as a subgroup within indo-aryan