Factors Associated with Language Delay in 12-Month-to-3-Year-Old Children—A Real-World Vietnam Case–Control Study

Objective: Language delay (LD) is a common developmental condition in which children fail to achieve age-appropriate language milestones, affecting communication, cognition, and social integration. It affects approximately 1 in 14 preschool children and may have long-term consequences into adulthood. The period from 12 to 36 months is a critical window for language development, during which children begin to comprehend and produce their first words. Early identification of risk factors during this stage is essential for timely intervention. However, in Vietnam, data on factors associated with language delay in this age group remain limited. Therefore, this study aimed to identify factors associated with language delay in children aged 12–36 months. Methods: A case–control study was conducted, including 55 children with language delay and 55 typically developing children aged 12–36 months. Personal, familial, medical, and environmental data were collected using structured questionnaires. Univariate and multivariable logistic regression analyses were performed to identify factors associated with language delay. Results: A total of 110 children (43 boys and 67 girls) were included. The strongest risk factor was the use of screens to calm or occupy children (OR = 36.6; p < 0.001). Early bilingual exposure was a significant protective factor (OR = 0.12; p = 0.014), while shared reading or picture viewing showed a strong but borderline protective effect (OR = 0.23; p = 0.051). Conclusions: The use of screens to calm or occupy children was the main risk factor for language delay, whereas early bilingual exposure and shared reading or picture viewing were protective factors. These findings highlight the importance of limiting non-interactive screen use and promoting interactive language activities to support early language development.