The purpose of this research was to show how the syntactic and semantic components of the tense-aspect system interact during the acquisition process. Our methodology involved: (1) identifying predicates, (2) finding the initial occurrence of their tense-aspect morphology, and (3) observing the emergence of contrasts. Six children learning Polish and six children learning English, found in the CHILDES archives, were investigated. The average starting age of the children learning English was 1;11, and 1;8 for the children learning Polish. In the first analysis, we traced the same 12 verbs in both languages, and in the second analysis, we contrasted the acquisition patterns for a set of telic versus atelic predicates. We tracked the verbs/predicates from the starting age to 4;11 or the child's final transcript. In English, progressive aspect is the marked form, and in Polish, perfective aspect is the marked form. This typological distinction has a significant effect of the acquisition patterns in the two languages. We argue that children acquire a multi-dimensional system having deictic relations as one of the basic dimensions. This process can be best understood within a functional theoretical framework having a well-defined syntactic-semantic interface.