The paper examines the construction of novel items in language and the reconstruction of old ones (forms and/or meanings/uses) by children. The corpus of data was collected from the spontaneous speech of Greek- and Russian-speaking children, in which significant parallels between the two languages were found. The coined items (created by children and not belonging to adult language) were considered as a result of children’s general language acquisition strategies and their creative practice, as well as an aspect revealing the limits of the language system’s potential. After the observation of characteristics noticed in innovative items, a general classification of children’s neologisms is proposed and some theoretical implications are discussed.