This study examined whether 12-month-olds will accept words that differ phonologically and phonetically from their native language as object labels in an associative learning task. Sixty infants were presented with sets of English word–object (N = 30), Japanese word–object (N = 15), or Czech word–object (N = 15) pairings until they habituated. Infants associated CVCV English, CCVC English, and CVCV Japanese words, but not CCVC Czech words, with novel objects. These results demonstrate that by 12 months of age, infants are beginning to apply their language-specific knowledge to their acceptance of word forms. That is, they will not map words that violate the phonotactics of their native language to objects.