Human speech production obeys the same acoustic principles as vocal production in other animals but has distinctive features: A stable vocal source is filtered by rapidly changing formant frequencies. To understand speech evolution, we examined a wide range of primates, combining observations of phonation with mathematical modeling. We found that source stability relies upon simplifications in laryngeal anatomy, specifically the loss of air sacs and vocal membranes. We conclude that the evolutionary loss of vocal membranes allows human speech to mostly avoid the spontaneous nonlinear phenomena and acoustic chaos common in other primate vocalizations. This loss allows our larynx to produce stable, harmonic-rich phonation, ideally highlighting formant changes that convey most phonetic information. Paradoxically, the increased complexity of human spoken language thus followed simplification of our laryngeal anatomy.

中文翻译：

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作为语音适应的人类声乐解剖学复杂性的进化损失

人类发声遵循与其他动物发声相同的声学原理，但具有独特的特征：稳定的声源通过快速变化的共振峰频率进行过滤。为了了解语音进化，我们检查了范围广泛的灵长类动物，将发声观察与数学建模相结合。我们发现源稳定性依赖于喉部解剖结构的简化，特别是气囊和声膜的损失。我们得出结论，声膜的进化损失使人类语音在很大程度上避免了其他灵长类动物发声中常见的自发非线性现象和声学混沌。这种损失使我们的喉部能够产生稳定、谐波丰富的发声，理想地突出传达大多数语音信息的共振峰变化。矛盾的是，