The interaction of tone and vowel quality in Optimality Theory: A study of Moscow Russian vowel reduction

•The paper develops an analysis of vowel-tone interaction in the framework of OT.•Alignment of two natural linguistic scales: the tonal scale and the sonority scale.•Vowels associated with the High tone maximise sonority.•Pretonic reduction in Russian is driven by the High tone.•Atonic reduction in Russian is driven by the pressure to minimise sonority.

Although the interrelation of tone and segmental quality is typologically unusual, cases of vowel-tone interaction have been reported in the literature. The present paper argues that tone can interact directly with vowel quality without mediating factors such as syllable structure or duration. The basic assumption is that tonally prominent units co-occur with prominent segments. In terms of Optimality Theory, this generalisation is expressed by the family of markedness constraints *H/≤a, which are derived by harmonic alignment of two natural linguistic scales, the tonal scale and the sonority scale. The proposed constraints are used in the analysis of vowel neutralisations found in immediately pretonic positions in the Moscow variety of Standard Russian. A characteristic trait of standard Russian is that it exhibits two-pattern vowel reduction: moderate reduction is found in immediately pretonic positions, while extreme reduction is found in atonic positions. Previous accounts have suggested that different degrees of reduction are due to iambic foot structure. This paper argues that such an approach is flawed and develops an OT analysis, which is based on the insight originally expressed by Bethin (2006) that vocalic neutralisations are driven by the High tone spread from the stressed syllable.