The main aim that this research wants to contribute is to find evidence for or against two theoretical approaches to the syntax and semantics of pronouns and the proposed uniformity of pronouns and definites in one of the approaches (Elbourne 2005,2013). Acquisitional research already knows a lot about the production and comprehension of both phenomena, but so far, there haven’t been many studies that concentrate on their correlation. Both production and comprehension data of children’s acquisition of pronouns and definites shall be taken into account to determine if and how these theoretical approaches can be tested.