Along the lines of population sizes, becoming human, and language evolution, this article had some interesting insights. I would love to hear your and @DennisVenema’s thoughts on it. The relevant bits:
"Resequencing studies have estimated the ancestral effective population size at 12,800 to 14,400, with a 5- to 10-fold bottleneck beginning approximately 65,000 to 50,000 y ago (although see ref. 15 for a bottleneck to only 450 individuals). It is generally assumed that the bottleneck occurred as a small group(s) with an effective population size of only approximately 1,000 to 2,500 individuals moved from the African continent into the Near East. … The loss of genetic variation during the Great Expansion is assumed to have resulted from the way the world was settled by hunter-gatherer groups that, after colonizing a new habitat and expanding there, shed small groups that founded new colonies nearby. This genetic sampling process led to the successive reduction of variation in the newly founded colonies, with the reduction being proportional to the number of founders. A set of 52 populations from all continents [the Human Genetic Diversity Panel (20) has been studied with two large sets of markers: 784 microsatellites (21, 22) and 650,000 SNPs (23)]. In a single reasonably homogeneous population, genetic diversity of biparentally transmitted DNA can be assessed efficiently by counting heterozygotes for all variants. The pattern of average heterozygosities of today’s populations suggest that, during the Great Expansion, there was a continuous decrease of genetic diversity with geographic distance from the place of origin in Africa (this takes account of the likely path of migration over land). The linear correlation between loss of genetic diversity and geographic distance from the origin of expansion in Africa is close to 90%. The Great Expansion is thus consistent with serial colonization and concomitant loss of genetic heterozygosity, a process called a serial founder effect (Fig. 2) (21, 24, 25)…
"Concordance Between Genes and Language.
The evolution of languages is rapid—in a few hundred years, a language may change enough to destroy mutual understanding between neighboring populations, or even between ancestors and their descendants 1,000 y later. Families of languages that are similar enough that most linguists recognize them as such have a common origin in the range of 10,000 y ago. There is a remarkable similarity between the linguistic tree and the genetic tree, confirming Darwin’s speculation that, if we knew the biological tree of humans, we could predict that of their languages (62). The first attempt to connect the two trees was made at a time when the linguistic tree was incomplete (63), but the similarity was clear and later shown to be statistically real (64). As might be expected, the geographical distribution of language families and that of genetic groupings of indigenous populations are also reasonably closely related.
“Beyond congruence in phylogenetic topology, other aspects of genes and languages show correlations stemming from deep population processes. A recent analysis of phonemic diversity in 504 worldwide languages shows that this diversity exhibits the same serial founder effect discussed earlier for genetic variation, namely a loss of phonemic diversity proportional to distance from Africa (65). Moreover, within Africa, the greatest diversity is in the southern central region. Although the regression of phonemic diversity on distance from Africa is not as strong as seen with DNA polymorphisms, this finding nevertheless suggests that the genetic and linguistic expansion from Africa could have been part of the same process…”