Multilingual diversity was the source of one of the most enduring anxieties in Indian nationalist thought. If one of the primary features of a nation was linguistic unity then how could India, with her many mother tongues, be a nation? If language formed the root of national unity by housing the most essential of national truths, impulses and aspirations then what hope did India have of holding her fragments together as multiple mother tongues whispered diverse aspirations, truths and impulses in her citizen’s ears? This concern about linguistic diversity had a number of significant implications for Indian nationalist thought about language. My paper focuses on one primary implication of this anxiety—the search for a pan Indian language that would bind the nation together- Hindustani. The need for such a language was coupled with a need to bestow on it a historic continuity that would bolster its claims as the museum of the inner life of Indians. As a result, twentieth century nationalist imagination of Hindustani emerged as a paradoxical thing—simultaneously new and ancient. l explore the intellectual history of the making of Hindustani as a possible Indian national language and its ultimate impossibility through an exploration of the work of one of the most influential linguists of twentieth century India, Suniti Kumar Chatterji. In his books about Bengali, Indo-Aryan, Hindi and North East Indian languages, Chatterji produced a narrative of Indian linguistic unity that justified the paradoxical life of Hindustani. In this paper, I trace how Chatterji’s argument about Hindustani engages with the Herderian imperative of linguistic unity and whether despite his explicit efforts, Chatterji is forced to produce a critique of western models of nationalism based on linguistic unity.<br/