ArticleBiology letters2020
Chimpanzee lip-smacks confirm primate continuity for speech-rhythm evolution.
Article in Biology letters, 2020. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 13 papers.
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Who cites it
13 citing papers in PubMed.
- Animal acoustic communication has a conserved optimal rhythm within the neural delta range.PLoS biology · 2026Article
- Third-order self-embedded vocal motifs in wild orangutans, and the selective evolution of recursion.Annals of the New York Academy of Sciences · 2025Article
- Generative vocal plasticity in chimpanzees.iScience · 2025Article
- Vocal Learning Versus Speech Evolution: Untangling a False Equivalence.Ecology and evolution · 2025Article
- Context-dependent rhythmicity in chimpanzee displays.Proceedings. Biological sciences · 2024Article
- Dog-human vocal interactions match dogs' sensory-motor tuning.PLoS biology · 2024Article
- Rhythms in Speech.Advances in experimental medicine and biology · 2024Review
- Open plains are not a level playing field for hominid consonant-like versus vowel-like calls.Scientific reports · 2023Article
- The (Co)Evolution of Language and Music Under Human Self-Domestication.Human nature (Hawthorne, N.Y.) · 2023Article
- Sociality predicts orangutan vocal phenotype.Nature ecology & evolution · 2022Article
- Faces and Voices Processing in Human and Primate Brains: Rhythmic and Multimodal Mechanisms Underlying the Evolution and Development of Speech.Frontiers in psychology · 2022Review
- Multilevel rhythms in multimodal communication.Philosophical transactions of the Royal Society of London. Series B, Biological sciences · 2021Review
- The Indexical Voice: Communication of Personal States and Traits in Humans and Other Primates.Frontiers in psychology · 2021Review
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Authors and funding
5 authors.
Funding
No grant is acknowledged in the PubMed record.
Abstract
Speech is a human hallmark, but its evolutionary origins continue to defy scientific explanation. Recently, the open-close mouth rhythm of 2-7 Hz (cycles/second) characteristic of all spoken languages has been identified in the orofacial signals of several nonhuman primate genera, including orangutans, but evidence from any of the African apes remained missing. Evolutionary continuity for the emergence of speech is, thus, still inconclusive. To address this empirical gap, we investigated the rhythm of chimpanzee lip-smacks across four populations (two captive and two wild). We found that lip-smacks exhibit a speech-like rhythm at approximately 4 Hz, closing a gap in the evidence for the evolution of speech-rhythm within the primate order. We observed sizeable rhythmic variation within and between chimpanzee populations, with differences of over 2 Hz at each level. This variation did not result, however, in systematic group differences within our sample. To further explore the phylogenetic and evolutionary perspective on this variability, inter-individual and inter-population analyses will be necessary across primate species producing mouth signals at speech-like rhythm. Our findings support the hypothesis that speech recruited ancient primate rhythmic signals and suggest that multi-site studies may still reveal new windows of understanding about these signals' use and production along the evolutionary timeline of speech.
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