Several studies agree that reading aloud for young children has a significant impact in raising children's levels of knowledge and vocabulary and, consequently, their oral linguistic competence (Mol, Bus and de Jong, 2009 for a meta-analysis), indicating that the extensive preparation of the adult (parent or teacher) can be necessary if we are to influence this linguistic competence. In this article, we discuss in what sense the knowledge of vocabulary and the linguistic structures that include it can contribute to the linguistic development of young children.