White matter in infancy is prospectively associated with language outcome in kindergarten

Language acquisition is of central importance to a child’s development. Although the trajectory of acquisition is shaped by input and experience postnatally, the neural basis for language emerges prenatally. Thus a fundamental question remains unexamined: to what extent may the structural foundations for language established in infancy predict long-term language abilities? In this longitudinal neuroimaging investigation of children from infancy to kindergarten, we find that white matter organization in infancy is prospectively associated with subsequent language abilities, specifically between: (i) the left arcuate fasciculus in infancy and subsequent phonological awareness and vocabulary knowledge, and (ii) the left corticospinal tract in infancy and phonological awareness and phonological memory in kindergarten. Results are independent of age and home literacy environment. These findings directly link white matter organization in infancy with language abilities after school entry, and suggest that structural organization in infancy sets an important foundation for subsequent language development.