This article presents results from a large population-based study of early communicative development in Norwegian children using an adaptation of the MacArthur-Bates Communicative Development Inventories, comprising 6574 children between 8 and 36 months. Data were collected via the Internet. In accordance with similar studies from other languages, it was found that vocabulary comprehension preceded vocabulary production, and that both use of gestures, comprehension and production of vocabulary, and grammatical complexity increased with age. Moreover, boys lagged behind girls in vocabulary production and comprehension, in grammatical complexity, and in certain types of imitation--this gender difference seems to come out more clearly in this study's data than in data from other languages.