Vowel harmony: transparent and opaque vowels

1. Introduction In linguistic theory, there is a tension between two core aims of the field: theoretical parsimony and empirical coverage of the remarkable diversity and specificity seen in linguistic data. Vowel harmony 1 and more specifically the two phenomena of transparency and opacity in vowel harmony which concern us in this paper provide prime examples of phonological research concerned with resolving this tension. Recent findings and promising new theoretical ideas on transparency and opacity indicate that our understanding of these phenomena is at a critical stage. The crucial future step will be the integration of the new data patterns with insights from theoretical analyses. This would require an improved understanding of the phonetic basis of vowel harmony, the nature and origin of the grammatical forces governing transparency and opacity, and finally an understanding of the organizational principles governing the resolution of these forces within and across languages.