Although we know much about the conditions under which children demonstrate selective social learning, we have a limited understanding of the cognitive mechanisms by which children's selectivity manifests. Here, we report findings from a brain electrophysiological (ERP) study designed to determine the extent to which words presented by ignorant speakers were later both familiar to children and associated with semantic meaning. Forty‐eight children (mean age = 6.5 years) first experienced novel word training from either a knowledgeable or an ignorant speaker. Children's ERPs were subsequently recorded as they heard a recording of the speaker using the novel word, followed by a picture of either the object the word was paired with during training (congruent) or a distractor object that was also present during training (incongruent). Children trained by a knowledgeable speaker showed both N200 and N400 effects to the incongruent word–referent pairings, thereby suggesting that the novel words were both familiar and bore a semantic association. In contrast, children trained by an ignorant speaker demonstrated only the N200 effect, thereby suggesting that the word–referent links were familiar, but not associated with semantic meaning. These findings provide evidence that selective word learning involves the disruption of processes specifically associated with semantic consolidation of word learning events. This study used a combined word training ‐ ERP paradigm to investigate the cognitive mechanisms underlying children's selective word learning. Children who were trained novel word‐referent links by an ignorant speaker encoded the links, but did not associate semantic meaning to these links, suggesting that selective word learning involves the disruption of processes specifically associated with the semantic consolidation of word learning events.