Transparency, locality, and contrast in Uyghur backness harmony

Theories of vowel harmony have wrestled with the formal challenges of transparency, notably the increased expressivity resulting from non-local dependencies. However, experimental work has demonstrated on a number of occasions that 'transparent' vowels actually undergo harmony (e.g., Gick, Pulleyblank, Campbell, & Mutaka, 2006), re-establishing the role of locality in the analysis of harmony. Existing work on backness harmony in Uyghur argues that /i/ is transparent to harmony, with some proposing that this falls out from the absence of contrastive /w/ in the language (e.g., Vaux, 2000). This paper examines the distribution of surface [i] and [w] within roots and suffixes to assess their phonological status, as well as their participation in harmony. Results support the case that there are no long-distance dependencies in Uyghur, suggesting that harmony is truly local in the language. Results for root-internal [i] and [w] are less clear; evidence from most speakers supports an allophonic relationship, while some evidence for other speakers suggests the possibility of contrastive /i/ and /w/.