The development of canonical proportion as a function of community, multilingualism, and target language’s syllable complexity

This study investigates the development of canonical proportion (CP), an indicator of vocal maturity, across diverse language and environmental contexts. Using the Speech Maturity Dataset (SMD) comprising 369 children, aged 0;2-6;4, across ten different languages and cultures, we explore the influence of multilingual exposure, language syllable complexity, and community type (industrialized, non-industrialized) on early phonological development. We find that monolingual children display higher CP measures than their multilingual peers. Additionally, CP is higher for children learning languages with simple syllable complexity than those with more complex syllables. We also find no significant differences in the CP trajectory of children from industrialized versus non-industrialized communities. We integrate these findings focusing with the broader literature on early language development, and highlight the importance of diversifying our participant samples to better understand the complex relationship between various dimensions of language exposure, social environment, and language development.