This paper presents a study into the Hindi-Urdu 'na' as a sentence-final particle. Although also used as a topic marker and negation, 'na' occurs sentence-finally across clause-types. In light of the data, we think the following hypothesis offers the best fit: 'na' signals the speaker’s belief that the content of na’s containing clause is a reasonable inference, given what’s common ground. Notably, in addition to other clause-types, we explore na's distribution in exclamations and exclamatives. We link our work to recent (...) research on the polar question particle 'kya' in Hindi-Urdu. (shrink)