In this study explanations are sought for the often reported associations in child language between tense/aspect morphology and situation type. The study is done on the basis of adult-adult data, child language and input language to the children. First of all it is shown that the associations are natural, since they are strong in adult-adult English as well. Only in the early stages does child language differ from this distribution, in that the associations are either stronger or different. Input data appear to account to a large extent for these differing patterns. An additional explanation is found in the discourse topics: within the context of talking about the here-and-now, the combinations of morphology and situation type that can be seen as unmarked suffice. In the context of talking about past events and of giving general comments about the world, marked combinations are necessary. It is shown that children in and their parents at the early ages mainly talk about the here-and-now, whereas adults among themselves hardly ever do so. Later, describing past events and commenting on the world becomes more frequent in child language and input, and, as a consequence, marked combinations of tense/aspect morphology and situation types increase in use
