2017 年 21 巻 1 号 p. 23-30
A set of hypotheses regarding the evolutionary emergence of human speech is proposed. Animal acoustical communication probably originated from noises contingent with respiratory gestures. These noises and orofacial movements were gradually ritualized, forming fixed action patterns for communication. Combinations of calls were used by young animals to induce parental behavior. This effect was utilized by male animals to attract females. Extremes of such vocalizations are songs, used for mate attraction and territorial defense in many species. Songs are an honest signal of vigor. Songs and behavioral contexts were gradually associated through a mutual segmentation process and proto-words emerged in ancestral hominids.