Do motor skills impact on language development between 18 and 30 months of age?

Despite recent evidence on the relation between motor development and language development in infancy, this relation is still little explored in the late second and third year. This study investigated whether gross and/or fine motor skills affect language outcomes in this age range and whether any such effects narrow over time to specific language categories related to motor experience, such as spatial vocabulary. Thirty-six Italian monolingual toddlers (58% girls) participated, divided into two groups based on their age. They were assessed twice: the younger group at 18 (Time-1) and 24 months (Time-2); the older group at 24 (Time-1) and 30 months (Time-2). At Time-1 motor and language abilities were measured using the Griffiths Mental Development Scales. At Time-2, only language outcomes (three vocabularies: nouns, predicates, and spatial terms) were assessed, using the Picture Naming Game-PiNG. Hierarchical linear regressions show that motor skills affect language abilities also in the late second and third year, but the impact varies according to the type of motor skills (gross vs. fine) and children's age. At 18 months, controlling for linguistic abilities, a global score of gross motor skills predicted predicate production, and a specific gross-motor coordination skill: general dynamic coordination (GDC) predicted noun production at 24 months. At 24 months, controlling for linguistic abilities, GDC predicted predicate production, and a combination of fine- and gross-motor coordination skills (bilateral coordination and GDC) predicted spatial vocabulary comprehension at 30 months. Overall, results suggest that the relation between motor and language development is not simple or stable over time, but rather dynamic.