This study investigates the development of canonical proportion (CP), an indicator of speech development, across diverse language and environmental contexts. Using the Speech Maturity Dataset (SMD) comprising 366 children, aged 0;2–6;4, across 10 different languages and cultures, we explore the influence of multilingual exposure, language syllable complexity, and community type (industrialised, non-industrialised) on CP. We find that monolingual children display higher CP measures than their multilingual peers. In addition, 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 industrialised versus non-industrialised communities. Integrating these findings in the broader literature, we highlight the importance of diversifying participant samples to capture the complex relationship between language exposure, social environment, and language development.
Tey et al. (2026) studied this question.