Optionality and locality: Evidence from Navajo sibilant harmony

While many phonological processes are local, consonant harmony is of interest phonologically because it can occur non-locally. Sibilant harmony in Navajo requires that sibilants within a word have matching anteriority specifications. The process is described as being sometimes mandatory and sometimes optional, but neither the statistical nature of the occurrence in optional settings nor the factors contributing to the optionality are fully understood. This paper provides preliminary investigation into these issues using the first person possessive morpheme, which is underlyingly /ʃi-/ but may harmonize to [si-]. Experiment 1, an online grammaticality judgment survey, reveals that the harmonized prefix is dispreferred in all environments. Experiment 2 presents acoustic data from three Navajo speakers: though none harmonize overtly, the spectral mean and lower bound of frication energy of the prefixal fricative are affected by the presence of [+anterior] sibilants in noun stems. The overall implication of these findings is that harmony is not only optional but is dispreferred or wholly absent for some speakers. While multiple factors are investigated, the only one that consistently affects harmony is adjacency of the trigger and target, indicating that, although consonant harmony may indeed be a non-local process, its occurrence is heavily mediated by distance. Kelly Harper Berkson: Indiana University. E-mail: keberkson@gmail.com