This prospective cohort study (Norway, 2023–2026) examined associations between screen use indicators — child daily screen time, child digital device ownership, parental social media use, and primary parent smartphone screen time — and children's receptive vocabulary and grammar development from ages 5 to 7 years (n=747), using latent growth modeling adjusted for parental education and household income.
Most child screen use measures were not linked to language growth. However, each additional hour/day of primary parent smartphone use was associated with 0.42 points slower annual growth in receptive vocabulary (95% CI, −0.66 to −0.18). Children who owned a digital device at ages 4–5 scored 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) at baseline compared to non-owners.
- Screen use was parent-reported, which may introduce recall and social-desirability bias. - The study is observational; residual confounding cannot be excluded despite adjustment for education and income. - The sample was recruited from Norwegian municipalities, limiting generalizability to other cultural or socioeconomic contexts.
Counsel families that **parental smartphone use** — not just child screen time — may matter for early language development; reducing caregiver smartphone use during child interaction is a practical, actionable target. Early personal device ownership in children under 5 is also associated with lower concurrent language scores and warrants discussion at well-child visits.
