Dual language learners (DLLs) - children who are learning and developing two languages - are among the fastest growing groups of young children in the United States and currently compose a third of the public preschool population. Although evidence suggests that preschool education is beneficial for DLLs, little is known about which instructional supports in the preschool classroom best promote DLLs’ early learning skills. Drawing on a newly-collected sample of Spanish-speaking DLLs in an English-dominant, mixed-delivery public preschool system for children in low-income families (Head Start; school-based pre-k), this paper focuses on two instructional dimensions of the preschool classroom expected to support DLLs’ learning: supports for home language and supports for English acquisition. We test for associations between these classroom supports and DLLs’ English language skills, quantitative reasoning skills assessed in English, and home language skills at the end of the preschool year, and whether any such associations are moderated by the proportion of DLLs in the classroom. Controlling for baseline skills, results indicate positive associations between classroom supports for home language and quantitative reasoning skills and Spanish expressive vocabulary skills at the end of preschool. Associations varied by proportion of DLLs in the classroom. Supports for English acquisition did not predict any outcomes. This study adds to an emerging body of research suggesting classroom instructional supports for DLLs’ home language may be important not just for the maintenance of children's home language, but also for the acquisition of foundational pre-math skills. Additionally, findings suggest support for home language is possible even in preschool classrooms where the teacher does not speak the home language. The DLL composition of the classroom also warrants attention as a moderator of these associations.

双语学习者（DLL）-正在学习和发展两种语言的儿童-是美国成长最快的幼儿群体之一，目前占公共学龄前儿童的三分之一。尽管有证据表明，学前教育对DLL有好处，但对于学前班教室中哪些教学支持最能促进DLL的早期学习技能知之甚少。本文以英语为主的混合交付公共学前教育系统中针对低收入家庭儿童的新收集的西班牙语DLL样本为研究对象（Head Start；基于学校的学前班），本文着重于两个教学方面预期支持DLL学习的学前班：支持家庭语言和英语习得。我们测试了这些教室支持与DLL的英语语言技能，以英语评估的定量推理技能以及学龄前结束时的家庭语言技能之间的关联，以及是否通过DLL在教室中的比例来缓和任何此类关联。控制基线技能后，结果表明，学龄前结束时，家庭语言的课堂支持和定量推理技能与西班牙语表达性词汇技能之间存在正相关关系。关联因教室中DLL的比例而异。英语习得的支持并没有预示任何结果。这项研究增加了一个新兴的研究机构，表明课堂教学对DLL的家庭语言的支持可能不仅对维护儿童的家庭语言很重要，而且还需要掌握基础的数学技能。此外，研究结果表明，即使在老师不讲母语的学前班教室中，也可以支持母语。DLL的课堂组成也值得引起注意，它们是这些协会的主持人。