Elika Bergelsona,b,1 and Richard N. Aslinb:

Infants start understanding words at 6 mo, when they also excel at subtle speech–sound distinctions and simple multimodal associations, but don’t yet talk, walk, or point. However, true word learning requires integrating the speech stream with the world and learning how words interrelate. Using eye tracking, we show that neophyte word learners already represent the semantic relations between words. We further show that these same infants’ word learning has ties to their environment: The more they hear labels for what they’re looking at and attending to, the stronger their overall comprehension. These results provide an integrative approach for investigating home environment effects on early language and suggest that language delays could be detected in early infancy for possible remediation.