The origins of human speech are obscure; it is still unclear what aspects are unique to our species or shared with our evolutionary cousins, in part due to a lack of a common framework for comparison. We asked what chimpanzee and human vocal production acoustics have in common. We examined visible supra-laryngeal articulators of four major chimpanzee vocalizations (hoos, grunts, barks, screams) and their associated acoustic structures, using techniques from human phonetic and animal communication analysis. Data were collected from wild adult chimpanzees, Taï National Park, Ivory Coast. Both discriminant and principal component classification procedures revealed classification of call types. Discriminating acoustic features include voice quality and formant structure, mirroring phonetic features in human speech. Chimpanzee lip and jaw articulation variables also offered similar discrimination of call types. Formant maps distinguished call types with different vowel-like sounds. Comparing our results with published primate data, humans show less F1–F2 correlation and further expansion of the vowel space, particularly for [i] sounds. Unlike recent studies suggesting monkeys achieve human vowel space, we conclude from our results that supra-laryngeal articulatory capacities show moderate evolutionary change, with vowel space expansion continuing through hominoid evolution. Studies on more primate species will be required to substantiate this.

This article is part of the theme issue ‘Voice modulation: from origin and mechanism to social impact (Part II)’.

人类语言的起源尚不清楚。目前还不清楚哪些方面是我们物种所独有的，或者是我们的进化表亲所共有的，部分原因是缺乏一个共同的比较框架。我们询问黑猩猩和人类发声声学有什么共同点。我们使用人类语音和动物交流分析技术，检查了四种主要黑猩猩发声（呼喊、咕噜声、吠叫、尖叫）的可见喉上发音器官及其相关的声学结构。数据收集自科特迪瓦塔伊国家公园的野生成年黑猩猩。判别式分类程序和主成分分类程序都揭示了呼叫类型的分类。辨别声学特征包括语音质量和共振峰结构，反映人类语音中的语音特征。黑猩猩的嘴唇和下巴的发音变量也提供了类似的呼叫类型区分。共振峰图通过不同的类似元音的声音来区分呼叫类型。将我们的结果与已发表的灵长类动物数据进行比较，人类表现出较少的 F1-F2 相关性和元音空间的进一步扩展，特别是对于 [i] 声音。与最近的研究表明猴子获得了人类元音空间不同，我们从结果中得出结论，喉上发音能力显示出适度的进化变化，元音空间扩展通过类人猿进化而持续。需要对更多灵长类物种进行研究来证实这一点。

本文是“声音调制：从起源、机制到社会影响（下）”主题的一部分。