Development of Canonical Proportion Continues Past Toddlerhood

A key aspect of the development of speech production, the emergence of vocalizations that combine consonants and vowels, is captured by a measure called canonical proportion (CP). Yet this measure has mainly been studied among children under 12 months old learning English. We study CP in naturalistic speech in a cross-linguistic sample of 129 children aged 1 to 72 months. We show that children’s CP continues to grow well after 12 months, and that CP development may vary cross-linguistically/culturally. This study has implications for how we conceptualize and monitor the development of speech production and showcases how coarse, semi-automated approaches can be used to study cross-cultural speech development from natural production data.