The Evolution of Language: Three Things We’ve Learnt

March 31, 2016 by Ellen 13 Comments

A coupla hundred years ago, our good ol’ mate Darwin thought up this totally radical idea called evolution. This had two noticeable results:

• the church got their knickers in a twist,
• and it revolutionised our understanding – of biology, humanity, pretty much EVERYTHING-y.

Cheeky Darwin and his pesky evolution theory got the Church’s knickers in a twist.

Since then, all manner of disciplines have co-opted the evolution concept: stellar evolution! Directed evolution! Music evolution!

Linguistics is no different. In my last post, I briefly compared biological evolution to language evolution. We also touched on this topic in our foray into the origins of language.

This time round, we’re gonna get fully sucked into the mind-bending twister of language evolution. Here’s three wicked things we’ve learnt from investigating how our mother tongues have transformed.

 

1. What Ancient People Were Like

By tracing the evolution of languages back in time, we’re essentially creating a knowledge-wormhole to ancient societies and their cultures.

Take the Proto-Indo-Europeans, for example. We talked a lot about their zombie PIE language in the previous post – but what I didn’t mention is that we can learn a lot about PIE society based on this reconstructed vocabulary. The words used by people are a mirror to their culture – in the PIE case, a ~~time travel mirror~~.

We know that the PIEs lived in a location with snow because they (and all their daughter languages) used the word sneig^wh-. Similarly, we reckon they lived inland, because they didn’t have a general word for sea. We even know they worshipped a sky god and had domesticated both horses and cattle. You can read more about PIE society here.

Proto-Indo-European society didn’t have a specific word for “sea” so they probably lived inland.

2. How Humans Populated the Corners of the Earth

By examining how languages have evolved and diversified, we can also map out migration patterns across the globe.

For example, researchers built a phylogenetic tree of around 40 indigenous languages from North America and Central Siberia. This allowed them to construct a model of how the languages diffused across the two continents.

The results suggest that dispersal first occurred down the western coast of North America, followed by a “back-migration” into Siberia and then further diffusion throughout inland North America.

That is, there wasn’t a one-way migration from Asia to the New World via the Bering Land Bridge – human migration is more complex than we first thought. This lends support to the “Out of Beringia” theory.

Map showing the dispersion of people and their languages from Beringia. Reproduced from this paper.

Another migration-mystery that has bewildered researchers for aaaages is the “Austronesian Expansion” – or how the heck the Polynesians made it to all those tiny Pacific islands.

There are two main theories: a gradual settlement over 30,000 years (the “slow boat”) and a more recent “pulse-pause” scenario with ancestors migrating from Taiwan some 5,000 years ago.

To test these hypotheses, linguists constructed an evolutionary tree of Pacific languages. But they weren’t the only ones investigating this conundrum: biologists constructed a classic phylogenetic tree of a species of gut bacteria. By combining the evidence from both approaches, the scientists were able to discern the probable migratory routes – and they matched pretty well with the Taiwan-origin hypothesis. The “pulse-pause” pattern of migration was also replicated in the linguistic tree – it suggested one migration pulse of 7,000km over just 1,000 years.

Pretty cool, hey.

Linguistic evidence and genetic evidence from gut bacteria solved the Pacific migration mystery.

3. Language Evolution Really is like Biological Evolution

Evolution as a scientific theory has only been comprehensively analysed in its biological habitat. But it seems as though this concept may operate in a cultural domain too. This makes intuitive sense: cultures (and their languages) do change over time.

But the similarities go deeper than just a simple “shit changes” sense. Language is a complex adaptive system: it is an interconnected network of small, related parts (words) that work together to adapt to changes (cultural and environmental context) to ensure the survival of the collection as a whole (language).

Recently, some scientists have been explicitly adopting a Darwinian approach to culture.

In one study from 2008, linguists observed the evolution of an artificial language from random to highly structured, in a controlled laboratory setting.

The artificial language becomes more precise and more ordered over time – it evolves! Figure reproduced from this paper. 

These experiments revealed that, “languages transmitted culturally evolve in such a way as to maximise their own transmissibility.”

In non-wanky-science-speak: the language itself evolves in order to increase the chance it will be passed on (and stay “alive”). It’s like language is a cultural parasite, using human hosts to reproduce.

A language parasite and a human host? (Based on the real-life tongue-eating louse)

Evolutionary theorists have also used biology techniques to reconstruct language family trees using vocabulary “genes.” (Just like we talked about with the reconstruction of Proto-Indo-European.)

Using statistics, they were able to figure out that 10-30% of all words emerged during language splitting events – i.e. word “speciation” occurs in bursts of change, not gradually. This mirrors what we observe in biological evolution: about 22% of all genetic differences arise from bursts of sudden change.

Perhaps these “word explosion” events may reflect groups of people trying to establish a unique identity through their own distinct language. Kinda like those kids in primary school who thought they were so cool and different speaking Gibberish.

One Last Thing

If we take a step back and look at all these cool language evolution-y things, we can see how diverse this field is: from neuroscience to linguistics to evolutionary biology to archaeology (and more).

We’ll continue exploring this cross-disciplinary complexity in posts to come. Keep checkin’ in for more rad yarns! (And more shitty illustrations.)