2025/10/04
paper · doi:10.34842/ldr2025-838
The second year of life is characterized by rapid expressive vocabulary growth for most children, however, there is also substantial individual variation. Can variation in expressive vocabulary skill identified very early in the second year, prior to 16 months, provide useful signals about children’s later development? Here, we examined growth trajectories in expressive vocabulary from 12-24 months of age in Hebrew-speaking children grouped according to their earliest expressive vocabulary level. Caregivers of 92 toddlers completed the Hebrew adaptation of the MacArthur-Bates Communicative Development Inventories: Words & Gestures three times, every few months. Children were classified at first administration (12-16 months) as either lower (n = 21, ≤ 25th percentile) or higher (n = 71, > 25th percentile) in expressive vocabulary. Trajectories of growth were significantly delayed in the lower group, compared to the higher group, but the shapes of trajectories were generally similar. Critically, children with initial weaker receptive skills (< 25th percentile) had significantly shallower growth trajectories than children with stronger comprehension skills. Moderate delays in receptive vocabulary (< 50th percentile) were not informative in predicting growth trajectories for children with lower initial expressive vocabulary scores. These results suggest that lower expressive and receptive skills defined as early as 16 months provide useful information about future expressive vocabulary growth. Theoretical and clinical implications are discussed.