A comparison of worldwide phonemic and genetic variation in human populations
AbstractWorldwide patterns of genetic variation are driven by human demographic history. Here, we test whether this demographic history has left similar signatures on phonemes—sound units that distinguish meaning between words in languages—to those it has left on genes. We analyze, jointly and in parallel, phoneme inventories from 2,082 worldwide languages and microsatellite polymorphisms from 246 worldwide populations. On a global scale, both genetic distance and phonemic distance between populations are significantly correlated with geographic distance. Geographically close language pairs share significantly more phonemes than distant language pairs, whether or not the languages are closely related. The regional geographic axes of greatest phonemic differentiation correspond to axes of genetic differentiation, suggesting that there is a relationship between human dispersal and linguistic variation. However, the geographic distribution of phoneme inventory sizes does not follow the predictions of a serial founder effect during human expansion out of Africa. Furthermore, although geographically isolated populations lose genetic diversity via genetic drift, phonemes are not subject to drift in the same way: within a given geographic radius, languages that are relatively isolated exhibit more variance in number of phonemes than languages with many neighbors. This finding suggests that relatively isolated languages are more susceptible to phonemic change than languages with many neighbors. Within a language family, phoneme evolution along genetic, geographic, or cognate-based linguistic trees predicts similar ancestral phoneme states to those predicted from ancient sources. More genetic sampling could further elucidate the relative roles of vertical and horizontal transmission in phoneme evolution.
Experimental evidence for the co-evolution of hominin tool-making teaching and language
AbstractHominin reliance on Oldowan stone tools—which appear from 2.5 mya and are believed to have been socially transmitted—has been hypothesized to have led to the evolution of teaching and language. Here we present an experiment investigating the efficacy of transmission of Oldowan tool-making skills along chains of adult human participants (N=184) using five different transmission mechanisms. Across six measures, transmission improves with teaching, and particularly with language, but not with imitation or emulation. Our results support the hypothesis that hominin reliance on stone tool-making generated selection for teaching and language, and imply that (i) low-fidelity social transmission, such as imitation/emulation, may have contributed to the ~700,000 year stasis of the Oldowan technocomplex, and (ii) teaching or proto-language may have been pre-requisites for the appearance of Acheulean technology. This work supports a gradual evolution of language, with simple symbolic communication preceding behavioural modernity by hundreds of thousands of years.
Link (Closed Access)
The Lalibela Rock Hewn Site and its Landscape (Ethiopia): An Archaeological Analysis
This article presents the methods employed at the site of Lalibela, Ethiopia during the 2009, 2010, 2011 and part of the 2012 campaigns, as well as the first results obtained. This site consists of a group of rock-cut churches attributed to the sovereign of the same name, King Lalibela, who we know to have reigned in the late 12th century and in the first third of the 13th century. Cut out of solid rock, Lalibela is an exceptional archaeological site since most of the traces of its early phases were eliminated in the process of its transformation. The site thus presents a significant challenge for historians and archaeologists. How is it possible to write its history without excavation? Geomorphological observations of the region offer new keys for understanding Lalibela; identification of the spoil heap, in which we discovered a clear stratigraphy confirming the existence of different cutting phases; the topographic and taphonomic analysis of the remains, and investigations in the cemetery of Qedemt, revealed that the site was formed in multiple phases, probably reflecting a long occupation sequence spanning at least eleven centuries (from the 10th to the 21st century).