Abstract
In the field of language development, one interesting issue is how Japanese-speaking
children acquire the case markers that play a role in understanding a sentence’s struc-
ture, because previous studies reported that caregivers often omit them when talking
to their children (e.g., Rispoli, 1991). Although grasping the characteristics of parental
input on case markers is crucial for understanding a child’s acquisition process of them,
the studies so far have shown insufficient data to clarify the qualitative and develop-
mental characteristics of case marker inputs because of small sample size or a limited
target age. This study used a larger sample of mothers (N=52) with children who
ranged from 1 to 3 to measure their tendency to talk to their children using a struc-
tured production-elicited task. Our results revealed that Japanese-speaking mothers
tended to omit case markers more frequently when speaking to children than to adults.
The omission rate also differed depending on the child’s age, the type of case mark-
ers, verb transitivity, and maternal views about speech to children. Additionally, the
mothers tended to omit arguments more frequently when speaking to children, sug-
gesting that Japanese-speaking children have fewer opportunities for listening to case
markers because of sentence simplification. These findings have important implications
for investigating the relationship between parental language input and child language
development.
