Abstract

Exposure to conversational turn-taking is a key predictor of individual differences in language development. However, studies examining its role in Korean-learning infants remain limited, with previous research relying mostly on short-term designs and automatized measurements. This study manually measured the frequency of turn-taking in interactions between 14- to 20-month-old Korean infants and their mothers. It also categorized whether the turn-taking was mother- or infant-initiated to systematically re-examine its short- and long-term effects of turn-taking on expressive vocabulary acquisition. Results show that the turn-taking frequency significantly predicted vocabulary acquisition at the time of participation and at 54 months. Additionally, turn-taking fully mediated the relationship between socioeconomic status and vocabulary development. Mother-initiated turn-taking had a significant long-term impact, underscoring the importance of caregiver-led conversations in early language acquisition.