Taken together, these findings suggest that with vocabulary development, young learners may develop more stringent criteria for the sound sequences that are possible word forms, thereby constraining the search for words to link with meanings. This selectivity may promote efficient lexical acquisition in two ways. First, infants will avoid wasting cognitive resources entertaining illegal word forms as labels for concepts. Second, successful learning of new legal or canonical words may strengthen emerging representations of the phonotactic constraints and probabilistic patterns present in the ambient language.