The central set of data investigated here is based on the analysis of the features of first verbal productions in Italian. Since the appearance of verbs implies the mastery of a mapping procedure between syntactic positions and semantic roles, the syntactic regularities found for each lexical verb class suggest that the relation at the syntax-semantics interface is well-established early on. The non-adult-like sentences are those which involve the mastery of the scope-discourse semantic interface or higher functional syntactic categories. The analysis of the delay in the production and comprehension of some constructions here uncovers some general characteristics of language acquisition devices.