sentence processing among native vs. nonnative speakers: implications for critical period hypothesis

the present study intended to investigate the processing behavior of 2 groups of l2 learners of english (high and mid in proficiency) and a group of english native speakers on english active and passive reduced relative clauses. three sets of tasks, an offline task, and 2 online tasks were conducted. results revealed that the high-proficiency group’s performance was the same as that of the native group in all the 3 tests in terms of accuracy and processing behavior. accordingly, it was concluded that proficient l2 learners can achieve native-like performance. also, opposed to maturational propositions on adult l2 learning following the critical period hypothesis, the high-proficiency participants showed native-like behavior on the l2 structures. we suggest that the amount of exposure to an l2 can be a defining factor for l2 learners to perform in a native-like manner.