Hierarchies are the hidden backbones of complex systems and their analysis allows for a deeper understanding of their structure and how they evolve. We consider languages also to be complex adaptive systems with several intricate networks that capture their structure and function. Hence, we decided to analyze the hierarchical organization of historical syntactic networks to understand how syntax evolves over time. We created these networks from a corpus of German texts from the 11th to 17th centuries, focusing on the hierarchical levels of these networks. diachronically and to map them to specific communicative needs of speakers. We developed a framework to empirically track the emergence of syntactic structures diachronically, enabling us to map the communicative needs of speakers with these structures. We named these syntactic structures "syntactic communicative hierarchies." We showed that the communicative needs of speakers are the organizational force of syntax. Thus, we argue that the emergence of syntactic communicative hierarchies plays a crucial role in shaping syntax over time. This may indicate that languages evolve not only to increase the efficiency of transferring information, but also to increase our capacity, as a species, to communicate our needs with more and more sophisticated abstractions.

翻译：层级结构是复杂系统隐藏的骨架，对其分析能深入理解系统的结构及演化过程。我们将语言也视为复杂的自适应系统，其结构与功能由多个精密网络共同支撑。因此，我们决定分析历史句法网络的层级组织，以探究句法如何随时间演变。我们基于11至17世纪德语文本语料构建了这些网络，重点关注其层级结构。通过历时性研究，我们将这些层级映射至说话者的特定交际需求。我们开发了一个实证框架来追踪句法结构的历时涌现过程，从而将说话者的交际需求与这些结构对应起来，并将此类句法结构命名为"句法交际层级"。研究表明，说话者的交际需求是句法组织化的驱动力量。据此，我们论证句法交际层级的产生在塑造句法历时演变中起着关键作用。这可能表明语言演化不仅是为了提升信息传递效率，更是为了增强人类这一物种通过日益精妙的抽象概念来沟通需求的能力。