Koch Rajbongshi Bhasar Utpotti, Bikash aru Namkaran: Eti Parjalachana (Origin, Development, and Nomenclature of the Koch Rajbongshi Language: A Review) by Utpal Singha is a critical linguistic and historical study published in November 2023. Written in Assamese, the book traces the ancient roots of the Koch Rajbongshi language, presenting a detailed case for its status as a distinct, independent language rather than a regional dialect of Assamese or Bengali.
Through comparative etymological analysis, the author cross-references modern Koch Rajbongshi vocabulary with ancient texts like the Charyapada and early Sankari literature to demonstrate the language's antiquity. The work also re-evaluates the ethnographic history and identity construction of the Koch and Rajbongshi people within the historical frameworks of the Pragjyotisha-Kamrupa and Kamata kingdoms. By challenging established colonial historiography, this book serves as an essential resource for researchers studying Northeast Indian linguistic evolution, pre-colonial identity, and regional history.