Previous research has indicated that explicit information (EI) about either the first language (L1) or second language (L2) along with task-essential practice can facilitate L2 learning (e.g., Fernández, 2008; McManus, 2022). However, little research has examined L1–L2 contrastive EI with L1/L2 practice. Targeting plural-marking accuracy, the present study sought to fill this gap by exposing 127 Japanese intermediate learners of English to six online treatment sessions across four conditions: (1) non-contrastive EI (pluralization rule explanation) + L2 practice, (2) contrastive EI + L2 practice, (3) as per Condition 2 + additional L1 practice (application of L2 pluralization to L1 through the Japanese suffix –tachi), and (4) using prepositions as a control, non-contrastive EI (prepositional rule explanation) + L2 practice. Accuracy was tested at pre/post/delayed intervals using an acceptability judgement task (reading) and a picture description task (writing). Statistical analyses demonstrated greater gains from the contrastive variables in the immediate post-test, with L1 practice appearing especially beneficial, despite improvements diminishing in the delayed post-test. Supplementary data from retroactive interviews and questionnaire responses indicated favourable orientations towards the intervention. The study advances understanding of how EI and practice type can be used to maximize L2 learning through web-based practices tailored to the nature of the learning problem.

先前的研究表明，有关第一语言 (L1) 或第二语言 (L2) 的显式信息 (EI) 以及任务必需练习可以促进 L2 学习（例如，Fernández，2008 年；McManus，2022 年）。然而，很少有研究考察 L1-L2 EI 与 L1/L2 练习的对比。针对复数标记的准确性，本研究试图通过让 127 名日本中级英语学习者参加六次在线治疗课程来填补这一空白，这些治疗课程涉及四种条件：(1) 非对比 EI（复数规则解释）+ L2 练习，(2)对比 EI + L2 练习，(3) 根据条件 2 + 额外的 L1 练习（通过日语后缀 – tachi将 L2 复数应用于 L1），以及 (4) 使用介词作为对照，非对比 EI（介词规则解释） ) + L2 练习。使用可接受性判断任务（阅读）和图片描述任务（写作）在前/后/延迟间隔测试准确性。统计分析表明，在立即的后测试中，对比变量带来了更大的收益，尽管在延迟的后测试中改进有所减弱，但 L1 练习似乎特别有益。回顾性访谈和问卷调查的补充数据表明了干预措施的有利方向。该研究加深了人们对如何利用 EI 和实践类型通过针对学习问题的性质量身定制的基于网络的实践来最大化第二语言学习的理解。