On the replicator dynamics of lexical stress: accounting for stress-pattern diversity in terms of evolutionary game theory

This paper accounts for stress-pattern diversity in languages such as English, where words that are otherwise equivalent in terms of phonotactic structure and morphosyntactic category can take both initial and final stress, as seen in 'lentil - hotel, 'envoy - degree, 'research(N) - research(N) and 'access(V) - access(V). Addressing the problem in general and abstract terms, we identify systematic conditions under which stress-pattern diversity becomes stable. We hypothesise that words adopt stress patterns that produce, on average, the best possible phrase-level rhythm. We model this hypothesis in evolutionary game theory, predict that stress-pattern diversity among polysyllabic word forms depends on the frequency of monosyllables and demonstrate how that prediction is met both in Present-Day English and in its history.