Dating the Origin of Language Using Phonemic Diversity

Language is a key adaptation of our species, yet we do not know when it evolved. Here, we use data on language phonemic diversity to estimate a minimum date for the origin of language. We take advantage of the fact that phonemic diversity evolves slowly and use it as a clock to calculate how long the oldest African languages would have to have been around in order to accumulate the number of phonemes they possess today. We use a natural experiment, the colonization of Southeast Asia and Andaman Islands, to estimate the rate at which phonemic diversity increases through time. Using this rate, we estimate that present-day languages date back to the Middle Stone Age in Africa. Our analysis is consistent with the archaeological evidence suggesting that complex human behavior evolved during the Middle Stone Age in Africa, and does not support the view that language is a recent adaptation that has sparked the dispersal of humans out of Africa. While some of our assumptions require testing and our results rely at present on a single case-study, our analysis constitutes the first estimate of when language evolved that is directly based on linguistic data

A dispersal of Homo sapiens from southern to eastern Africa immediately preceded the out-of-Africa migration

Africa was the birth-place of Homo sapiens and has the earliest evidence for symbolic behaviour and complex technologies. The best-attested early flowering of these distinctive features was in a glacial refuge zone on the southern coast 100-70 ka, with fewer indications in eastern Africa until after 70 ka. Yet it was eastern Africa, not the south, that witnessed the first major demographic expansion, ~70-60 ka, which led to the peopling of the rest of the world. One possible explanation is that important cultural traits were transmitted from south to east at this time. Here we identify a mitochondrial signal of such a dispersal soon after ~70 ka - the only time in the last 200,000 years that humid climate conditions encompassed southern and tropical Africa. This dispersal immediately preceded the out-of-Africa expansions, potentially providing the trigger for these expansions by transmitting significant cultural elements from the southern African refuge.Portuguese foundation for science and technology (FCT), through the project PTDC/EPH-ARQ/4164/2014 partially funded by European Regional Development Fund (FEDER) (COMPETE 2020 project 016899), through a personal grant to D.V. and P.S. was supported by FCT, ESF and POPH through the FCT Investigator Programme (IF/01641/2013). P.S., D.V. and E.C.-S. acknowledge FCT IP and ERDF (COMPETE2020 – POCI) for the CBMA strategic programme UID/BIA/04050/2013 (POCI-01-0145-FEDER-007569). T.R. is supported by a FCT grant (SFRH/BPD/108126/2015) and acknowledges the project [NORTE-01-0145-FEDER-000013], supported by NORTE 2020-Portugal 2020, through FEDER for institutional support. M.B.R. and M.S. received support from a Leverhulme Doctoral Scholarship programme. E.C.-S. acknowledges project UID/MAT/00144/2013 funded by FCT (Portugal) with MEC and FEDER under PT2020. Authors acknowledge the use of cluster SEARCH funded through Search-ON2: HPC infrastructure of UMinho, (NORTE-07-0162-FEDER-000086), co-funded by ON.2-O Novo Norte under NSRF through ERD

78,000-year-old record of Middle and Later Stone Age innovation in an East African tropical forest

The Middle to Later Stone Age transition in Africa has been debated as a significant shift in human technological, cultural, and cognitive evolution. However, the majority of research on this transition is currently focused on southern Africa due to a lack of long-term, stratified sites across much of the African continent. Here, we report a 78,000-year-long archeological record from Panga ya Saidi, a cave in the humid coastal forest of Kenya. Following a shift in toolkits ~67,000 years ago, novel symbolic and technological behaviors assemble in a nonunilinear manner. Against a backdrop of a persistent tropical forest-grassland ecotone, localized innovations better characterize the Late Pleistocene of this part of East Africa than alternative emphases on dramatic revolutions or migrations.peer-reviewe