The current study examines whether a difference exists in the emergence of nouns and verbs in children’s early vocabularies in languages possessing different parameter settings with respect to null arguments. Using data from CHILDES, proportions of noun and verb types are examined in the speech of native English-, Spanish-, and Mandarin-speaking children with ages ranging from 1;7-2;0, 2;1-2;5, and 2;6-2;11 and their respective caregivers. English- and Spanish-speaking children exhibit a noun bias across all age groups, yet consistent results are not obtained for Mandarin-speaking children in the first two age groups, although a verb bias is found in the third. While results for caregivers indicate that the input does differ across language types, their within-language results do not match those for children. The findings indicate that the structure of a language is more dominant than the input in determining the existence of a noun bias in children’s early vocabularies.