Additional language (L2/Ln) research largely focuses on learners whose first languages are spoken and who are learning additional spoken languages. In the past few decades, sign languages have become increasingly popular for hearing students in schools. These students must not only learn the vocabulary and grammar of sign languages but also manage a different modality (that is, the channels of production and reception of language) than their first language. This raises questions about the role of both language and modality in the L2/Ln learning of sign languages for non-signers. In other cases, deaf and hearing signers of a sign language learn a different sign language, raising questions about L2/Ln learning in the signed modality. This Special Issue consists of empirical contributions and a conceptual review article that examine how language and modality shape the learning of sign languages as additional languages. Theoretical issues concerning learning a sign language as another language are discussed.

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特刊简介：学习手语作为附加语言：考虑语言和形态特定因素

附加语言 (L2/Ln) 研究主要关注母语为母语且正在学习附加口语的学习者。在过去的几十年里，手语在学校里越来越受到听力学生的欢迎。这些学生不仅必须学习手语的词汇和语法，而且还必须管理与母语不同的模式（即语言的产生和接收渠道）。这就提出了关于语言和形态在非手语者手语学习中的作用的问题。在其他情况下，聋哑人和听力正常的手语手语者学习不同的手语，从而引发了有关手语模式中 L2/Ln 学习的问题。本期特刊包含实证贡献和概念性评论文章，探讨语言和情态如何塑造手语作为附加语言的学习。讨论了有关学习手语作为另一种语言的理论问题。