The Impact of Spaced and Massed Practice on Deliberate Learning of English Opaque Idioms across L2 Proficiency Levels: A Mixed-Methods Research

The effect of spacing, specifically spaced and massed practice, on learning and retention of different skills and knowledge components has been studied extensively in various disciplines, such as experimental psychology, cognitive psychology, and education. In vocabulary research, spaced practice has been found to bear superior effects on single-word vocabulary learning, compared with massed practice. However, the effects of spaced and massed practice on learning and retention of Multi-Word Expression (MWEs), such as idioms, by L2 learners of different proficiency have not yet been sufficiently researched. The present thesis seeks to address this gap by examining the impact of spaced and massed practice on deliberate learning of English opaque idioms across L2 proficiency levels. This thesis consists of three parts. In the first part, a methodological systematic review of spaced/massed practice studies in applied linguistics/SLA since 2000 to 2023 was conducted. The results of the review informed the field by delineating the present state of research into spacing and suggesting ways it can be described more systematically. The results also informed methodological decision of the present study. In the second part, an experimental classroom-based study was conducted with 199 English L2 learners (65 low-, 68 mid-, and 66 high-proficiency ones) who learned 40 opaque idioms explicitly via flashcard technique through either spaced or massed practice. The learning and retention of the idioms were measured via cued-form recall, meaning recall, and short story writing posttests in immediate, short-delayed (12 days after treatment), and long-delayed (100 days after treatment) posttests. The main results of this part were that firstly, on both cued-form recall and meaning-recall tests, high-proficiency and mid-proficiency groups benefitted most from spaced practice while the low-proficiency group benefitted most from massed practice. Secondly, while massed practice was found more effective on L2 idiom learning, spaced practice was found more effective on L2 idiom retention. Third, in the short story test, it was found that high-proficiency group had the best performance in all types and times of posttests. In the third part of the thesis, 30 of the participants were interviewed to obtain their opinions on the two treatment approaches (spaced and massed practice). The results showed that unlike the low-proficiency and mid-proficiency learners who had false metacognition and metamemory on spacing, the high-proficiency learners did not.