The world’s languages vary in almost every conceivable way, yet children readily learn their native language. Understanding how children can acquire such a diversity of different languages has been a long-standing goal for psychological science, yet current acquisition research is dominated by studies of children learning one particular language: English. In this article, we argue that progress toward this goal will require systematic comparisons between different languages. We propose three levels of comparison: coarse-grained comparisons contrasting unrelated languages to confirm or refute broad theoretical claims, fine-grained comparisons between closely related languages to investigate the impact of specific factors on acquisition outcomes, and within-language comparisons targeting the impact of socio-communicative differences on learning. This three-pronged comparative approach to language acquisition promises to provide new insights into the mechanisms and processes by which children acquire their native tongue under such varied linguistic and socio-communicative conditions.

世界上的语言几乎以各种可以想象的方式变化，但孩子们很容易学习他们的母语。了解儿童如何获得如此多样化的不同语言一直是心理科学的长期目标，但目前的习得研究主要是对儿童学习一种特定语言的研究：英语。在本文中，我们认为要实现这一目标，需要对不同语言进行系统比较。我们提出了三个级别的比较：粗粒度的比较不相关的语言，以证实或反驳广泛的理论主张，密切相关的语言之间的细粒度比较，以调查特定因素对习得结果的影响，以及针对语言影响的语言内比较。学习上的社会交际差异。