The sound change *s- > n- in Arapaho

The sound change *s > n in initial position in Arapaho is unparalleled in the world’s languages, and previous attempts at explaining it have failed to produce a convincing account of its intermediate stages. This article presents two hypotheses to account for the correspondence between PA *s- and Arapaho n-, taking into account not only the individual steps of this particular proto-phoneme, but the evolution of the whole consonant system. It shows that the change *s > n in initial position only appears to reflect an unnatural development: it can in fact be explained in terms of a sequence of natural changes and mergers.