This study examined the extent to which language-switching practice enhanced L2 learners’ L2 grammatical processing by improving language selection abilities. Thirty-six English-speaking learners of French completed the same language-switching practice of L1 and L2 sentences, but received different types of pre-practice explicit information (EI) designed to address L2 learning difficulties resulting from crosslinguistic influence: one group (n = 17) received EI about English–French differences for viewpoint aspect, and a second group (n = 19) received EI about viewpoint aspect in French only. This design investigated the extent to which pre-practice linguistic knowledge moderated the effectiveness of the language-switching practice. Longitudinal analyses showed that increasing amounts of practice improved language selection abilities (increased accuracy, reduced reaction time costs), but only for learners who received EI about L1-L2 differences. These findings that language-switching was moderated by type of pre-practice EI have important implications for theories of L2 learning and instruction.

中文翻译：

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检查语言转换练习对减少 L2 语法处理中跨语言竞争的有效性

本研究考察了语言转换练习在多大程度上通过提高语言选择能力来增强二语学习者的二语语法处理。36 名讲英语的法语学习者完成了 L1 和 L2 句子的相同语言转换练习，但接受了不同类型的练习前显式信息 (EI)，旨在解决跨语言影响导致的 L2 学习困难：一组（n = 17) 收到关于英语-法语观点差异的 EI，第二组 (n = 19) 仅收到关于法语观点方面的 EI。该设计调查了练习前的语言知识在多大程度上影响了语言转换练习的有效性。纵向分析表明，增加练习量可以提高语言选择能力（提高准确性，降低反应时间成本），但仅限于接受 EI 的学习者关于 L1-L2 差异。这些发现语言转换受到练习前EI类型的调节，这对L2学习和教学理论具有重要意义。