Department of Cognitive and Behavioral Science, Graduate School of Arts and Sciences, University of Tokyo, 3-8-1 Komaba, Meguro-ku, 153-8902 Tokyo, Japan.
Proc Biol Sci. 2011 Dec 22;278(1725):3662-9. doi: 10.1098/rspb.2011.0518. Epub 2011 May 4.
Languages, like genes, evolve by a process of descent with modification. This striking similarity between biological and linguistic evolution allows us to apply phylogenetic methods to explore how languages, as well as the people who speak them, are related to one another through evolutionary history. Language phylogenies constructed with lexical data have so far revealed population expansions of Austronesian, Indo-European and Bantu speakers. However, how robustly a phylogenetic approach can chart the history of language evolution and what language phylogenies reveal about human prehistory must be investigated more thoroughly on a global scale. Here we report a phylogeny of 59 Japonic languages and dialects. We used this phylogeny to estimate time depth of its root and compared it with the time suggested by an agricultural expansion scenario for Japanese origin. In agreement with the scenario, our results indicate that Japonic languages descended from a common ancestor approximately 2182 years ago. Together with archaeological and biological evidence, our results suggest that the first farmers of Japan had a profound impact on the origins of both people and languages. On a broader level, our results are consistent with a theory that agricultural expansion is the principal factor for shaping global linguistic diversity.
语言和基因一样，通过一个带有修饰的演化过程进行演变。这种生物和语言演化之间惊人的相似性，使我们能够运用系统发生学的方法来探索语言以及说这些语言的人是如何通过演化历史彼此关联的。利用词汇数据构建的语言系统发生树迄今为止揭示了南岛语系、印欧语系和班图语系使用者的种群扩张。然而，系统发生方法在多大程度上能够描绘语言演化的历史，以及语言系统发生树揭示了人类史前史的哪些方面，必须在更广泛的范围内进行更彻底的研究。在这里，我们报告了 59 种日语语言和方言的系统发生树。我们利用这个系统发生树来估计它的根的时间深度，并将其与日本起源的农业扩张情景所建议的时间进行比较。与该情景一致的是，我们的结果表明，日语是由大约 2182 年前的一个共同祖先演化而来的。结合考古学和生物学证据，我们的结果表明，日本的第一批农民对人和语言的起源都产生了深远的影响。在更广泛的层面上，我们的结果与一个理论一致，即农业扩张是塑造全球语言多样性的主要因素。
