Children produce Nouns and Verbs practically as soon as they start talking. Do they however treat these words differently as a function of the category they belong to? Do they ascribe to them different meanings on the basis of their morphosyntactic features and/or differentiate them with the formal means at their disposal? To answer this question we consider evidence coming from two sources of data. On the one hand, results of analyses of speech production provided by the longitudinal studies of naturally-occurring adult-child interaction, through the study of all the prenominal and preverbal positions in relation to the production of fillers, and through the study of the relevant phonomorphological variation in words that are verbs in the language. On the other hand, results of a cross-sectional comprehension study in which 2 to 4 yrs old children are led to retrieve the meaning of words on the unique basis of category-specific formal markings.