Languages vary considerably in syntactic structure. About 40% of the world’s languages have subject–verb–object order, and about 40% have subject–object–verb order. Extensive work has sought to explain this word order variation across languages. However, the existing approaches are not able to explain coherently the frequency distribution and evolution of word order in individual languages. We propose that variation in word order reflects different ways of balancing competing pressures of dependency locality and information locality, whereby languages favor placing elements together when they are syntactically related or contextually informative about each other. Using data from 80 languages in 17 language families and phylogenetic modeling, we demonstrate that languages evolve to balance these pressures, such that word order change is accompanied by change in the frequency distribution of the syntactic structures that speakers communicate to maintain overall efficiency. Variability in word order thus reflects different ways in which languages resolve these evolutionary pressures. We identify relevant characteristics that result from this joint optimization, particularly the frequency with which subjects and objects are expressed together for the same verb. Our findings suggest that syntactic structure and usage across languages coadapt to support efficient communication under limited cognitive resources.

中文翻译：

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跨语言词序变化反映了依赖性和信息局部性的进化压力


语言的句法结构差异很大。世界上大约 40% 的语言具有主语-动词-宾语顺序，大约 40% 的语言具有主语-宾语-动词顺序。大量的工作试图解释这种跨语言的词序变化。然而，现有的方法无法连贯地解释各个语言中词序的频率分布和演变。我们认为，词序的变化反映了平衡依赖局部性和信息局部性的竞争压力的不同方式，即当元素在句法上相关或上下文信息彼此相关时，语言倾向于将元素放在一起。利用 17 个语系 80 种语言的数据和系统发育模型，我们证明语言的进化是为了平衡这些压力，这样词序的变化就会伴随着说话者交流的句法结构的频率分布的变化，以保持整体效率。因此，词序的变化反映了语言解决这些进化压力的不同方式。我们确定了这种联合优化产生的相关特征，特别是同一动词的主语和宾语一起表达的频率。我们的研究结果表明，跨语言的句法结构和用法能够相互适应，以支持有限认知资源下的有效沟通。