Screen Use and Children's Language Development From Ages 5 to 7 Years.

IMPORTANCE: Concerns about screen use and early language development are widespread, and prior research has reported mixed findings. Many studies have not distinguished baseline differences from developmental change, leaving uncertainty about whether screen use is associated with actual language development in early childhood. OBJECTIVE: To examine associations between children's and parental screen use and children's language development from ages 5 to 7 years. DESIGN, SETTING, AND PARTICIPANTS: This population-based prospective cohort study included children recruited through municipalities across Norway in 2023. Children were followed up annually for 3 waves. Data were analyzed from September 2025 to March 2026. EXPOSURES: Parent-reported child daily screen time (weekday and weekend weighted average), child digital device ownership, maternal and paternal daily social media use, and primary parent smartphone screen time at the onset of the study. MAIN OUTCOMES AND MEASURES: Receptive vocabulary and receptive grammar were assessed annually using the British Picture Vocabulary Scale and the Test for Reception of Grammar. Latent growth modeling was used to estimate baseline language levels and developmental trajectories from ages 5 to 7 years, adjusting for parental education and household income. RESULTS: A total of 747 children (mean [SD] age, 4.9 [0.3] years; 360 of 718 female [50.1%]) were included in this study. Most screen use indicators were not associated with children's language growth. However, primary parent smartphone screen time was associated with slower growth in receptive vocabulary; each additional 1 hour per day was associated with 0.42 slower annual growth in receptive vocabulary raw score (95% CI, -0.66 to -0.18). Children who owned a digital device at age 4 to 5 years scored lower at baseline as follows: 5.13 points lower in receptive vocabulary (95% CI, -7.43 to -2.82) and 4.56 points lower in receptive grammar (95% CI, -7.56 to -1.55) compared with children who did not own a device. CONCLUSIONS AND RELEVANCE: In this cohort study, primary parent smartphone screen time was associated with slower growth in children's receptive vocabulary, whereas children's digital device ownership was associated with lower concurrent language performance. These findings highlight the importance of considering screen use within the broader family context when evaluating children's language development and are potentially informative for parents and clinicians.