The dates on the later (second) genetic bottleneck are actually early than you are suggesting Dr. Dick…and coincides generally with the Lake Toba eruption. Some have quibbled with the evidence that the bottleneck occurs lightly after the eruption, the non-correlation of climate change (glaciation) with the eruption, and a number of other elements…but it seems likely that these lag times are explicable from statistical errors in the different systems of dating.

Some have suggested that the bottlenecks, particularly the first, may relate to the speciation event that led to anatomically modern Homo sapiens…and Stanford’s Richard Klein has long suggested the second may have helped the “gene for language” spread…resulting in the movement out-of-Africa and a new development of Upper Paleolithic culture.

The problem with Klein’s view is that African sites are demonstrating that most of the elements of the Upper Paleolithic` jewellery, beads, rock art, blade lithics, bone tools with hafting are all earlier than the second bottleneck. And H.s.sapiens was able to occupy areas in the Middle East during non-glacial periods. But that area was “African” in fauna at that time. What’s fascinating is that modern humans move outside the African “faunal zone” when the UP tool pattern becomes widely used within Africa (i.e. when i actually firmly replaces other cultural competitors) and DURING an ice age that follows the Toba event. The first push appears to be tropical and coastal through SE Asia and to Australia. But then about 35,000 the moderns move into glacial maxima Europe and into Northern Asia. At that time they diversified their economic abilities and solved the issue of dealing with seasonal climates with very cold winters.

IMO there’s not much evidence that language was a single genetic “mutation” (this is a misreading of the FoxP data) or absent in earlier populations. It seems that linguistic capabilities are based on lots of genetic-cultural feedback shifts and that U.P. isn’t an all or nothing thing either. But the cultural complex seems stunning (and seemed even more “revolutionary” in the past when we lacked a firm appreciation of the African record and dates) when compared to earlier Middle Stone Age (aka Mousterian) and Acheulean industries.

Tambora was on the mainland of Java. It erupted in the 1600’s and killed over a 100,000 people in the actual eruption and subsequent famine due to destroyed rice fields. Destroyed a fairly sophisticated kingdom in the southwest of Java as a consequence.