This issue was designed to include a wide range of research on children's second language learning. Here we provide a short overview of each of the articles contained in this issue, many of which bring up novel ideas and topics, as well as new takes on familiar themes that sometimes challenge prior conceptions and, ideally, inspire new understandings of child language acquisition, and policies, and practices in instructed settings. The 15 articles in this issue are based in instructed and naturalistic settings and include reviews and experimental work, and collectively represent learners between 5 to 18 years old. The language backgrounds include Mandarin (first language [L1]), Arabic (L1), Basque (L1), Cantonese (L1), English (second language [L2]), Hebrew (L1, L2), Spanish (L1, L2), and Thai (L1). Topics include the uniqueness of child second language acquisition (SLA); learning in majority language classrooms; best practices in bilingual schooling, cognition, and SLA in younger learners; testing and assessment relating to age and language choice; and methodological contributions that arise from the particular challenges of researching child second language development in instructed and naturalistic settings.

中文翻译：

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探索儿童第二语言习得 (SLA) 的独特性：学习、教学、评估和实践

本期旨在包括对儿童第二语言学习的广泛研究。在这里，我们简要概述了本期中包含的每篇文章，其中许多提出了新颖的想法和主题，以及对熟悉主题的新看法，这些主题有时会挑战先前的概念，理想情况下，可以激发对儿童语言习得的新理解，以及指导环境中的政策和实践。本期的 15 篇文章基于指导性和自然主义的设置，包括评论和实验工作，共同代表 5 至 18 岁的学习者。语言背景包括普通话（第一语言[L1]），阿拉伯语（L1），巴斯克语（L1），粤语（L1），英语（第二语言[L2]），希伯来语（L1，L2），西班牙语（L1，L2） , 和泰语 (L1)。主题包括儿童第二语言习得（SLA）的独特性；在多数语言教室学习；年轻学习者在双语教育、认知和 SLA 方面的最佳实践；与年龄和语言选择相关的测试和评估；以及在指导性和自然主义环境中研究儿童第二语言发展的特殊挑战所产生的方法论贡献。