Second language acquisition depends on the experience of the target language. Accounts of successful L2 acquisition have accordingly emphasized the importance of the quality of the input available to the learners. As a result, this study probes the impact of input quality (natural and instructional) on second language grammar knowledge of young children. 40 infants (4 to 5 years old) were selected as the sample size in this study. The results revealed that both natural and instructional input promoted the target grammar knowledge in both grammaticality judgment tasks and elicited oral imitation tasks effectively. But it supports the superiority of instructional input over natural input in promoting second language grammar achievement.
Keywords: Grammar Achievement, Input Quality, Instructional Input, Natural Input
