As a language spreads, more foreigners come to learn it as adults (thanks to conquest and trade, for example). Since languages are more complex than they need to be, many of those adult learners will— Stalin-style—ignore some of the niceties where they can. If those newcomers have children, the children will often learn a slightly simpler version of the language from their parents.
随着一门语言的传播，越来越多的外国人成年后开始学习新的语言(例如，由于征服和贸易)。由于语言比它们需要的复杂得多，许多成年学习者将会——斯大林式地——尽可能地忽略一些细微的差别。如果这些新来者有孩子，孩子们通常会从他们的父母那里学习语言的简化版本。
But a new study, conducted at the Max Planck Institute for Psycholinguistics at Nijmegen in the Netherlands, has found that it is not entirely foreigners and their sloppy ways that are to blame for languages becoming simpler. Merely being bigger was enough. The researchers, Limor Raviv, Antje Meyer and Shiri Lev-Ari, asked 12 groups of four strangers and 12 groups of eight to invent languages to describe a group of moving shapes on the screen. They were told that the goal was to rack up points for communicating successfully over 16 rounds. (They “talked” by keyboard and were forbidden to use their native language, Dutch.)
但荷兰奈梅亨马普心理语言学研究所进行的一项新研究发现，语言变得越来越简单，并不完全是外国人和其马虎作风造成的。仅仅变大就足够了。研究人员Limor Raviv、Antje Meyer和Shiri Lev-Ari让12组每组4个陌生人和12组每组8个陌生人发明语言来描述屏幕上一组移动的图形。他们被告知目标是通过16轮的成功沟通来获得分数。(他们通过键盘“交谈”，被禁止使用母语荷兰语。)

Over time both big and small groups got better at making themselves understood, but the bigger ones did so by creating more systematic languages as they interacted, with fewer idiosyncrasies. The researchers suppose that this is because the members of the larger groups had fewer interactions with each other member; this put pressure on them to come up with clear patterns. Smaller groups could afford quirkier languages, because their members got to “know” each other better.
随着时间的推移，大群体和小群体都能更好地让自己被理解，但更大的群体做到沟通，是因为他们在互动时创造了更系统的语言，而没有那么多的特质。研究人员认为，这是因为较大群体的成员彼此之间的互动更少；这给他们带来了压力，要求交流模式更清晰。更小的群体可以使用更奇怪的语言，因为成员可以更好地“了解”彼此。
Neither the more systematic nor the more idiosyncratic languages were “better”, given group size: the small and large groups communicated equally well. But the work provides evidence that an idiosyncratic language is best suited to a small group with rich shared history. As the language spreads, it needs to become more predictable.
考虑到群体的规模、更系统的语言和更特殊的语言都不是“更好”的:小群体和大群体沟通得同样好。但这项研究证明，一种特殊的语言最适合拥有丰富共同历史的一小群人。随着传播，语言需要变得更加可预测。
Taken with previous studies, the new research offers a two-part answer to why grammar rules are built—and lost. As groups grow, the need for systematic rules becomes greater; unlearnable in-group-speak with random variation won’t do. But languages develop more rules than they need; as they are learned by foreign speakers joining the group, some of these get stripped away. This can explain why pairs of closely related languages—Tajik and Persian, Icelandic and Swedish, Frisian and English—differ in grammatical complexity. In each couple, the former language is both smaller and more isolated. Systematicity is required for growth. Lost complexity is the cost of foreigners learning your language. It is the price of success.