This study investigated intra-learner variation in the effects of implicit and explicit focus on form (FonF) on second language (L2) acquisition of the English passive, an interface construction. The study employed a pretest-posttest-delayed posttest design, with five treatment sessions between the pretest and posttests. Implicit FonF was operationalized as textual enhancement (TE), and explicit FonF as consciousness-raising (C-R). Five different outcome measures were utilized to examine the respective treatment effects on the form, meaning, and function of the passive. Data were collected with four Korean high school students, two engaging in TE and the other two in C-R, whose developmental routes through the experiment were analyzed quantitatively and qualitatively. The results of the analysis showed that implicit and explicit FonF led to differential variation within each learner, not only across the outcome measures but also over time, yet were suggestive of a potential benefits to each for the different domains encompassed in the passive. These results are further discussed in relation to the learners’ proficiency levels and the types of errors they produced.

I. Introduction
II. Literature Review
    1. Previous Research on Implicit and Explicit FonF
    2. Intra-Learner Variation
    3. Research Question
III. Research Method
    1. Participants
    2. Target Construction
    3. Pedagogical Treatment
    4. Outcome Measures
    5. Method of Analysis
IV. Results
    1. Summary of the Results of Jung (2019)
    2. The Analysis of Intra-Learner Variation
V. Discussion
    1. Implicit FonF and Intra-Learner Variation
    2. Explicit FonF and Intra-Learner Variation
IV. Conclusion
References

• Ji-Yung Jung(Seoul National University)