Recently, many researchers have reported about how children acquire a word meaning. Especially some of them reported that the verb meaning development is delayed to that of noun. In these reports, they used the ANOVA (the ANalysis Of VAriance) for the detection of a difference in the behavioral data. But ANOVA is not a sufficient way of analysis in the sense that we can't know the detailed mechanism of the meaning acquisition in children. So, in this paper, we developed a model based analysis of behavioral data that enable more detailed structure estimation, and analyzed the children's word acquisition data with the method. From the analysis, we found a hierarchical mixture of binomial distribution with three sub-modules is a suitable model for the data. The parameter change in the model indicated that what is changing between three to five years infant is a choice of proper learning action from the recognition of verb/noun situation.
