The two properties that characterize Ablaut reduplication in English (chit-chat, dilly-dally) are: (1) identical vowel quantity in the stressed syllabic peaks, (2) maximally distinct vowel qualities in the two halves, with [i] appearing most commonly to the left and a low vowel to the right. In addition, Ablaut reduplicatives are described as having a trochaic contour, yet there is a great deal of uncertainty regarding the stress on the second part of the formation. Historically, Ablaut reduplication appeared long after Copy reduplication (boo-boo, yo-yo) and flourished during the Renaissance; its productivity declined sharply in the twentieth century.

This article treats Ablaut reduplicatives as verbal art products, analogs of dipodic poetic meter. The naturalness of the template ensues from the interaction of conflicting segmental and prosodic constraints on identity and markedness. An independently established hierarchy blocks high back vowels from appearing in these forms. The height difference is a response to the principle of INTEREST which favors maximum perceptual differentiation between the stressed vowels. The linear ordering of the vowels correlates with domain-final lengthening. The ambiguity between compound stress and level stress that these words exhibit is related tentatively to the existence of a separate prosodic domain, a dipodic colon. The article provides Optimality-theoretic support for the analytical relevance of gradient phonetic properties and the relevance of the colon as a separate prosodic layer, and potentially enriches the taxonomy of metrical forms in English.