The emergence of the language system in the toddler brain

Toddlerhood is a time when children's language competence undergoes a dramatic transformation, making it a key period to examine the emergence of the brain's language system. Functional magnetic resonance imaging data from 29 awake toddlers (19-36 months) scanned on a child-friendly language task reveal that, already at this young age, areas in the left frontal and temporal cortex respond more to comprehensible language (i.e., videos of puppets speaking in English) than the control condition (matched videos with incomprehensible audio). Although the magnitude of response to language is substantially weaker than in adults, the topography is already adult-like, challenging claims that the frontal component or left-hemispheric dominance do not emerge until later in life.