Australian scientists have slipped another piece into the puzzle about human language development and it suggests that nearly half the world’s population may be more closely related than we think.
Analysis of ancient DNA has shed light on migration patterns, helping researchers trace the origins of some of the most widely spoken languages in the world.
Three billion people today speak a language that is part of the Indo-European family of languages, spanning Europe as well as Central, Western and South Asia, and these days the Americas.
But the reason why these languages are related has been a source of some argument for more than 200 years.
Now, Dr Wolfgang Haak from the Australian Centre for Ancient DNA at Adelaide University thinks he and his team may have uncovered a clue: the start of the agricultural era.
"Languages spread easier with a substantial number of people carrying it," he said.
"Linguists have always argued that the best candidate for the spread of an early Indo-European language must have been based on a substantial population movement, and if we look back in the past then there used to be only one predominate candidate that stood out that could not be ignore and that was the expansion of farmers, so people formed the farming-language dispersal hypothesis."
"Languages spread easier with a substantial number of people carrying it."
Dr Haak specialises in unravelling the oldest secrets of the fundamental human building blocks, DNA, with a particular focus on central Europe.
He said that by studying genetic sources, he could map population movements and likely language spread.
He was exploring his theory by testing the bones of old farmers, who muscled in on traditional hunter gatherers and had a profound impact on genetic makeup across Europe.
"Expanding farmer communities arrived in Europe about 7,500 years ago where we have a different type of ancestry, a different signal coming in that is unique across all farmers whether we look in Spain or in Germany or Hungary or even in Scandinavia," he said. "They all look very similar, which tells us they must have come from a similar geographic origin."
"If there's a signal strong enough then it is very likely it must have carried a common language was well."
But he said the big news that had just been published in the prestigious journal Nature was the discovery of a second major movement of people on the verge of the early bronze age, about 3000 years after that first wave.
He thought this discovery had brought scientists a step closer to pinpointing the very genesis of modern language and the answer appears to go back to a step of a different kind: the Russian steppes.
"We see a very strong signal coming from the Eurasian steppes," he said.
"Genes will always be silent on the type of language that people in the past spoke, but what we see and how we can contribute is we see population turnovers. In our case the second one towards the late Neolithic at the verge of the bronze age was unexpectedly big, so we’re seeing an influx from the steppe up to three quarters of the ancestry of central Europeans 5000 years ago comes from the steppe and that is a massive proportion that makes it very likely that it was not only the genes that came from the east but probably language as well."
Dr Haak said the theory was further supported by common elements in vocabularies, such as similar terms for inventions that were critical to farming like the wheel, the cart and the domestication of horses.
"It is only plausible to assume that once they share a certain economy, certain markets, social stratification or a social system, then it is only reasonable to assume that it would have had originally the same language before they split up into smaller regions," he said.
"Genes will always be silent on the type of language that people in the past spoke."
Dr Haak said it was a theory that should give people pause for thought before that criticise on the basis of race or go to war over territory.
"Why is it relevant? We have three billion speakers in the world speaking one of the 445 languages or dialects that can be summarised under Indo-European," he said.
"English is one of these but that also comprises a lot of Hindu/Urdu speakers in India, for example. Persian is Indo-European, and all the Romance languages. Maybe it can all be traced back to a number of mobile steppe cattle herders 5000 years ago."
