Interleaved Practice in L2 Grammar Learning: Variation Across Grammatical Patterns and Cue Reliability

ABSTRACT This study examined how interleaved and blocked practice schedules were associated with the learning of different grammatical patterns in adult second language (L2) learners, and how these patterns varied across learning contexts differing in cue reliability. Two experiments were conducted with native Mandarin‐speaking learners with no prior exposure to French. Experiment 1 examined interleaved and blocked practice across French morphological and syntactic constructions, with subject–verb agreement providing relatively consistent form–meaning mappings. Experiment 2 retained comparable syntactic constructions but replaced the French agreement system with a semi‐artificial morphological paradigm involving less consistent cue–outcome mappings. Across both experiments, interleaved practice was associated with increased difficulty during learning but generally higher performance at the test, particularly at the immediate posttest. Under more reliable cue conditions, this advantage diminished over time, whereas under less reliable cue conditions, it remained more evident at delayed testing. Differences between morphology and syntax were also observed across tasks and practice conditions, suggesting that practice‐schedule effects were related to the structural and processing properties of the target constructions. Overall, the findings suggest that the effectiveness of interleaving in L2 grammar learning depends not only on the practice schedule, but also on the characteristics of the target constructions and the reliability of the cues available to learners.