The state of documentation of Kalahari Basin languages

The Kalahari Basin is a linguistic macro-area in the south of the African continent. It has been in a protracted process of disintegration that started with the arrival of Bantu peoples from the north and accelerated dramatically with the European colonization emanating from the southwest. Before these major changes, the area hosted, and still hosts, three independent linguistic lineages, Tuu, Kx'a, and Khoe-Kwadi, that were traditionally subsumed under the spurious linguistic concept "Khoisan" but are better viewed as forming a "Sprachbund". The languages have been known for their quirky and complex sound systems, notably involving click phonemes, but they also display many other rare linguistic featuresa profile that until recently was documented and described very insufficiently. At the same time, spoken predominantly by relatively small and socially marginalized forager groups, known under the term "San", most languages are today, if not on the verge of extinction, at least latently endangered. This contribution gives an overview of their current state of documentation, which has improved considerably within the last 20 years

The history of sentence negation in the Gulf of Guinea Creoles

We discuss the emergence of the cross-linguistically marked discontinuous/final negation pattern in the four Gulf of Guinea Creoles by taking into account the different linguistic strata and their structural profiles that contributed to the formation of the protolanguage, in particular southern Nigerian and western Bantu languages. While the phonetic source of the final negation marker (fa/f/wa~va) in the creoles remains unclear, we argue that its syntax and functions, which also include emphasis, show a strong parallel with utterance-final markers in the contributing African languages. Although the trigger of these patterns should be sought in the earliest African contribution from Nigeria, their entrenchment and full grammaticalization can be attributed to heavy secondary contact with languages of the Kongo Bantu cluster

The genetic prehistory of southern Africa

Southern and eastern African populations that speak non-Bantu languages with click consonants are known to harbour some of the most ancient genetic lineages in humans, but their relationships are poorly understood. Here, we report data from 23 populations analyzed at over half a million single nucleotide polymorphisms, using a genome-wide array designed for studying human history. The southern African Khoisan fall into two genetic groups, loosely corresponding to the northwestern and southeastern Kalahari, which we show separated within the last 30,000 years. We find that all individuals derive at least a few percent of their genomes from admixture with non-Khoisan populations that began approximately 1,200 years ago. In addition, the east African Hadza and Sandawe derive a fraction of their ancestry from admixture with a population related to the Khoisan, supporting the hypothesis of an ancient link between southern and eastern AfricaComment: To appear in Nature Communication

New Insights into the Lake Chad Basin Population Structure Revealed by High-Throughput Genotyping of Mitochondrial DNA Coding SNPs

BACKGROUND: Located in the Sudan belt, the Chad Basin forms a remarkable ecosystem, where several unique agricultural and pastoral techniques have been developed. Both from an archaeological and a genetic point of view, this region has been interpreted to be the center of a bidirectional corridor connecting West and East Africa, as well as a meeting point for populations coming from North Africa through the Saharan desert. METHODOLOGY/PRINCIPAL FINDINGS: Samples from twelve ethnic groups from the Chad Basin (n = 542) have been high-throughput genotyped for 230 coding region mitochondrial DNA (mtDNA) Single Nucleotide Polymorphisms (mtSNPs) using Matrix-Assisted Laser Desorption/Ionization Time-Of-Flight (MALDI-TOF) mass spectrometry. This set of mtSNPs allowed for much better phylogenetic resolution than previous studies of this geographic region, enabling new insights into its population history. Notable haplogroup (hg) heterogeneity has been observed in the Chad Basin mirroring the different demographic histories of these ethnic groups. As estimated using a Bayesian framework, nomadic populations showed negative growth which was not always correlated to their estimated effective population sizes. Nomads also showed lower diversity values than sedentary groups. CONCLUSIONS/SIGNIFICANCE: Compared to sedentary population, nomads showed signals of stronger genetic drift occurring in their ancestral populations. These populations, however, retained more haplotype diversity in their hypervariable segments I (HVS-I), but not their mtSNPs, suggesting a more ancestral ethnogenesis. Whereas the nomadic population showed a higher Mediterranean influence signaled mainly by sub-lineages of M1, R0, U6, and U5, the other populations showed a more consistent sub-Saharan pattern. Although lifestyle may have an influence on diversity patterns and hg composition, analysis of molecular variance has not identified these differences. The present study indicates that analysis of mtSNPs at high resolution could be a fast and extensive approach for screening variation in population studies where labor-intensive techniques such as entire genome sequencing remain unfeasible

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