The present article argues that the idea of morphology-driven syntax carries over to first-language acquisition. Morphology encodes properties of functional categories, i.e. particular features and feature values that must be set according to the target (adult) language during the acquisition process. In agreement with previous findings concerning the acquisition of functional categories in the verbal domain, we discuss here some cross-linguistic data with respect to the nominal functional domain. In this respect, specificity can be said to develop stepwise, as the result of the valuation of the /number/ before the /person/ feature of noun phrases, which finds its reflection in the emergence of indefinite articles before definite articles.