The Causal Structure of Lenition: A Case for the Causal Precedence of Durational Shortening

Studies of variable lenition patterns converge on two phonetic properties as characteristic of lenition: reduced duration and increased intensity. However, the causal precedence of the two factors remains unclear. We focus on the causal structure of variable lenition. Study 1 examines the relationship between three correlates of lenition—speech rate, stress, and low information content—and their effect on reduced duration and increased intensity. We find that though increased intensity is more prototypically viewed as the core aspect of lenition, the effect of the three correlates on intensity is mediated by duration. Study 2 shows that all frequent lenition processes in the Buckeye corpus involve durational reduction. The contribution of this article is a proposal with a fairly simple principle, with few auxiliary assumptions: reduced duration precedes increased intensity in variable lenition.