Studies of brain‐language relations have focused almost exclusively on adults and, to a lesser extent, young children. Little, however, is known about the brain's involvement in language during the earliest stages of language acquisition, the focus of this study. Parents identified from a set of 10 words those that they believed were understood by their infant and those that were not known. Auditory event‐related potentials (ERPs) were then recorded from the frontal, temporal, and parietal scalp regions of the infants while they listened to this series of known and unknown words. The brain responses reliably discriminated between two sets of stimuli— words that were known to the infants and words that were unknown. Results resemble findings previously reported for older infants. These data extend the use of auditory ERPs in the study of early word meaning to 12‐month‐old infants and indicate marked similarities in responding between this age group and older infants.