An investigation of the first language acquisition of productive nouns in Inuktitut (Inupiaq) is presented. This study begins with descriptions of noun incorporation, relevant aspects of the structure of Inuktitut, and working criteria of productivity. Acquisition data from Inuktitut and corroborating data from Greenlandic are outlined and contrasted with evidence from Mohawk. Several structural and sociolinguistic explanations for the seemingly early acquisition of noun incorporation in Inuktitut in relation to its acquisition in Mohawk are offered: (1) placement of verbal affixation in relation to the incorporated noun differs significantly in the two languages; (2) the criteria for use of noun incorporation are more restrictive or clearer in Inuktitut; (3) noun incorporation is considered the most usual way to represent the concept in Inuktitut, and is therefore learned earlier; and (4) the Inuktitut living environment is more conducive to language learning than the Mohawk environment. A 12-item bibliography is included. (MSE)