Graduate School of Human and Environmental Studies, Kyoto University, Yoshida Nihonmatsu-cho, Sakyo-ku, Kyoto, 606-8501, Japan.
Primates. 2022 Sep;63(5):403-415. doi: 10.1007/s10329-021-00891-0. Epub 2021 Apr 5.
Human language is a multi-componential function comprising several sub-functions each of which may have evolved in other species independently of language. Among them, two sub-functions, or modules, have been claimed to be truly unique to the humans, namely hierarchical syntax (known as "Merge" in linguistics) and the "lexicon." This kind of species-specificity stands as a hindrance to our natural understanding of human language evolution. Here we challenge this issue and advance our hypotheses on how human syntax and lexicon may have evolved from pre-existing cognitive capacities in our ancestors and other species including but not limited to nonhuman primates. Specifically, we argue that Merge evolved from motor action planning, and that the human lexicon with the distinction between lexical and functional categories evolved from its predecessors found in animal cognition through a process we call "disintegration." We build our arguments on recent developments in generative grammar but crucially depart from some of its core ideas by borrowing insights from other relevant disciplines. Most importantly, we maintain that every sub-function of human language keeps evolutionary continuity with other species' cognitive capacities and reject a saltational emergence of language in favor of its gradual evolution. By doing so, we aim to offer a firm theoretical background on which a promising scenario of language evolution can be constructed.
人类语言是一种多成分的功能，包含几个子功能，其中每个子功能可能在其他物种中独立于语言而进化。在这些子功能中，有两个子功能或模块被认为是人类独有的，即层次语法（在语言学中称为“合并”）和“词汇”。这种特定于物种的特性阻碍了我们对人类语言进化的自然理解。在这里，我们挑战这个问题，并提出我们的假设，即人类的句法和词汇是如何从我们祖先和其他物种（包括但不限于非人类灵长类动物）的预先存在的认知能力中进化而来的。具体来说，我们认为合并是从运动动作规划中进化而来的，而人类词汇中的词汇和功能类别之间的区别是通过我们称之为“解体”的过程从动物认知中其前身进化而来的。我们的论点基于生成语法的最新发展，但通过借鉴其他相关学科的见解，关键是偏离了其核心思想的某些部分。最重要的是，我们坚持认为人类语言的每个子功能都与其他物种的认知能力保持着进化上的连续性，并反对语言的突发性出现，而赞成其逐渐进化。通过这样做，我们旨在提供一个坚实的理论背景，在此基础上可以构建语言进化的有希望的情景。
