Abstract
Decades of study documented that when children learn a language, especially content words, they use the linguistic information, which is often used in their input. However if the information does not appear in their input so often, children will not use it to learn the language. The current study investigates whether children use linguistic information in the learning of function words, especially in Japanese case markers. We introduced twenty-two five-year-olds to novel case markers, i.e., po and bi, which indicate the agent and patient of an action respectively at the sentence level. And we introduced po, bi in tow types of sentences. One is rich information sentence (SOV), other is poor information sentence (SV/OV). Children successfully learned bi in the SV/OV sentence, but not in the SOV sentence. These results indicate that the optimal context for case marker learning depends on numerous factors, especially the number of input they hear.
