Word form shapes are selected to be morphotactically indicative

Abstract

This paper explores the hypothesis that morphotactically ambiguous segment sequences should be dispreferred and selected against in the evolution of languages. We define morphotactically ambiguous sequences as sequences that can occur both within morphemes and across boundaries, such as final /nd/ or /mz/ in ModE, which occur in simple forms like wind or alms and in complex ones like sinned or seems. We test the hypothesis in two diachronic corpus studies of Middle and Early Modern English word forms ending in clusters of sonorants followed by /d/ or /t/ and /s/ or /z/. These clusters became highly frequent after the loss of unstressed vowels in final syllables and were highly ambiguous when they emerged. Our data show that the ambiguity of these final clusters was indeed reduced so that the distribution of the final clusters became increasingly skewed: clusters ending in voiceless coronals became significantly clearly indicative of simple forms, while clusters ending in voiced ones came to signal inflectional complexity more reliably.