Do motor skills impact on language development in toddlers?

Recent studies have shown that motor development and language development are more interrelated than it has previously been thought, mostly in the first years of life. It was found that the onset of motor milestones such as sitting and walking predicts both receptive and productive vocabulary at later ages (Libertus & Violi, 2016; West et al., 2019). However, attention has been paid to gross motor skills rather than to gross- and fine motor skills and motor coordination. Furthermore, the language outcome considered was mostly the general vocabulary. This study aims to: (1) deepen the relation between motor development and language development in the 2nd and 3rd year of life, assessing if/how gross and/or fine motor skills predict later receptive and productive vocabulary; (2) analyse if specific motor skills (both gross and fine) predict specific language skills, as the production of non-noun vs noun, and spatial vocabulary. 37 toddlers (23 females) divided in two age-groups: 13-19-month-olds, and 20-30-month-olds. The gross motor and fine motor skills were assessed using the Griffiths Mental Development Scales (GMDS-ER 2-8, 2006), subscales A: Locomotor, and D: Eye & hand coordination. The language skills were assessed using the GMDS, subscale C: Language, the McArthur-Bates Communicative Development Inventory-Italian vers.(Caselli et al., 2015), and 6 months later the PiNG test, subtests Nouns and Non-nouns (Bello et al., 2010). Hierarchical regression analyses were computed using language outcomes as target and gross and fine motor skills as predictors. The results have shown that fine motor skills combined with child gender in the youngers' group, and general motor coordination in the olders' group, predict non-noun productive vocabulary. These results extend previous evidence showing that in the 2nd and 3rd year of life the relationship between motor and later language skills involves fine motor skills.