The study assessed 30-month-old Mandarin-speaking children's awareness of aspectual distinctions involving the perfective marker le and the imperfective marker zhe in a preferential looking experiment. In the experiment, we presented our child subjects with a choice between two video clips (one depicting a closed event and the other depicting an on-going event), in the presence of an auditory stimulus (either the le sentence, the zhe sentence or the control sentence without any aspect marker). Children's looking behavior in the task was recorded and analyzed. The results revealed 30-month-old children's emerging sensitivity to the aspectual contrast between le and zhe. This was manifest by an increase in looking to the closed event when hearing the le sentence and an increase in looking to the on-going event when hearing the zhe sentence. The absence of le or zhe in the control sentence did not result in any increase or decrease in looking to either event. We also found that the effect of le on children's looking behavior was immediate whereas the effect of zhe was late. We attributed this difference to the facilitative role of le in children's sentence processing as well as their preference for the event boundary. The results lend support to the continuity view that functional morphemes like aspect markers are available to children early in language development.
Keywords: Early language comprehension; Grammatical aspect; Mandarin Chinese; Preferential looking.