Pirahã: a non-Turing-complete human language

http://www.newyorker.com/reporting/2007/04/16/070416fa_fact_colapinto

by nwatson • 17 years ago

85 39 17 years ago

nwatson2• 17 years ago

I submit this post in response to the article on scripting by Larry Wall (inventor of Perl) (see http://news.ycombinator.com/item?id=1033677, linked article http://www.perl.com/lpt/a/997).

In his article Mr. Wall says: "So it's rather ironic that my views on Postmodernism were primarily informed by studying linguistics and translation as taught by missionaries, specifically, the Wycliffe Bible Translators. One of the things they hammered home is that there's really no such thing as a primitive human language. By which they mean essentially that all human languages are Turing complete. When you go out to so-called primitive tribes and analyze their languages, you find that structurally they're just about as complex as any other human language. Basically, you can say pretty much anything in any human language, if you work at it long enough. Human languages are Turing complete, as it were."

The former Wycliffe Bible Translator/Summer Institute of Linguistics member Dan Everett reportedly counters this in the New Yorker article. "Everett, once a devotee of Chomskyan linguistics, insists not only that Pirahã is a severe counterexample to the theory of universal grammar but also that it is not an isolated case." This article is fascinating.

My grad school experience is too far in my past to exactly distinguish the nuances between "non-Turing-complete" and "not conforming to Chomsky's universal grammar" -- so have at it discussing the differences. In any case, this article describes a language where it's impossible to describe some common human ideas -- and not through lack of vocabulary, and perhaps not even because of inadequate grammar. Rather, the language betrays a completely different mindset where such ideas may not be relevant to survival.

Dan Everett, former Wycliffe missionary, reached crisis when he found no way to describe the notion of a God or Jesus Christ and their relation to humans to this Amazonian tribe. Mr. Everett decided that if there are people to whom one cannot convey a Christian message, the message must not be universal and cannot be real.

imok20• 17 years ago

One of the most remarkable parts of the language is that is does not have recursion. Nor does it have ways of explicitly differentiating temporally distant events.

This is an old article, but there are new ones a-comin'; the implications of Dan's work are just starting to be realized.

madair• 17 years ago

Really brilliant article. Thanks!

I'm wondering whether the premise of the language as not Turing complete holds up though. The article claims that the Piraha language lacks abstractions, including counting. Perhaps that could count as incompleteness, but I'm not so sure, and the article doesn't say enough to clear it up. Even if a person cannot use recursive linguistic forms, such as "I saw the dog by the river", they can say, "I saw the dog. The dog is by the river". Can they also say, "Another dog came to the river"? Is that enough context, without tracking the precise count?

Another thought, just because they don't care about a historical fact, is the fact that the story can be told in the language enough for completeness? Even without precise numeric counts?

Does Turing completeness even make sense as a description for a natural language?

nwatson2• 17 years ago

I'm using "Turing complete", perhaps incorrectly, in the sense that Larry Wall (inventor of Perl) did in a related article at http://www.perl.com/lpt/a/997, where he says: "Basically, you can say pretty much anything in any human language, if you work at it long enough. Human languages are Turing complete, as it were."

Pirahã seems to be a language where expressing certain kinds of complex ideas doesn't work. Sure, one might say "I saw the dog. The dog is by the river." I'm not sure that's the same as "I saw the dog which bit me while I was down at the river yesterday looking for fresh-water oysters to feed my mother-in-law to impress her because she's telling my wife I'm a loser because my alligator hunting sucks." My impression is it's hard to express the latter thought in the language, even breaking it up into separate sentences, without using recursion, which the language lacks, at some point.

wjdix2• 17 years ago

Everett's claims are extremely controversial. Also, this article is over two years old; hardly news. There have been several articles in the last few issues of Language have discussed the "exceptionality" of Piraha.

stevejohnson• 17 years ago

But it was posted as a direct response to a statement made in another article that was on the front page today, which sparked some discussion.

In this case, it's not about "news," it's about having an intelligent, informed discussion. And interesting stuff that is explained well.

rms• 17 years ago

There's nothing wrong with posting older articles here, though it's customary for the submitter or an editor to add a (2007) to indicate it is not new..

oconnor0• 17 years ago

Controversial. How so?

califragilistic• 17 years ago

For example: http://www.people.fas.harvard.edu/%7Enevins/npr09.pdf.

albertsun• 17 years ago

Does anyone have a recommendation for a good introduction to Chomsky's work for someone completely new to formal linguistics?

neilk• 17 years ago

Stephen Pinker's The Language Instinct is a good popularization.

Caveats: Pinker diverges from Chomsky on a lot of things, but he makes it fairly plain what's his and what is Chomsky. Pinker also gets a bad rap (unfairly in my opinion) of being a retrograde right-winger, because of his association with evolutionary psychology.

RyanMcGreal2• 17 years ago

Great find, thanks for sharing.

It's important to note that the case of the Pirahã doesn't salvage the Sapir-Whorf hypothesis. Whereas Whorf posited that the absence of a word for a given concept in a language means the people who speak that language cannot think about the concept, the evidence of the Pirahã seems to suggest the reverse: that the reason they don't have words for certain concepts is that they don't think about them.

ytinas5• 17 years ago

But this is circular. They don't think about it because they don't have a word to describe it... because they don't think about it....

RyanMcGreal2• 17 years ago

Nonsense. Extending a language to denote new concepts is easy. You can borrow a word from another language (ennui, schadenfreude); you can repurpose an existing word (broadcast, which once meant to stand in your field and throw seeds in every direction); and you can coin a new word (Twas brilling, and the slivy toves / Did gyre and gimble in the wabe).

The Pirahã don't have words for concepts that fall outside their cultural worldview for the simple reason that they have no need of such words.

joe_the_user2• 17 years ago

Piraha language exceptionalism is overdone (http://www.people.fas.harvard.edu/%7Enevins/npr09.pdf).

Even Everett Says: If you go back to the Pirahã language, and you look at the stories that they tell, you do find recursion. You find that ideas are built inside of other ideas, and one part of the story is subordinate to another part of the story. That's not part of the grammar per se, that's part of the way that they tell their stories. (http://www.edge.org/3rd_culture/everett07/everett07_index.ht...)

As the Harvard people argue, Everett kind-of redefined Piraha Grammar. So there isn't recursion in Everett's official grammar even through the Piraha use recursion in their communication by everyone admission.

inffcs00• 17 years ago

I think you have to read the full paragraph.

"If you go back to the Pirahã language, and you look at the stories that they tell, you do find recursion. You find that ideas are built inside of other ideas, and one part of the story is subordinate to another part of the story. That's not part of the grammar per se, that's part of the way that they tell their stories. So my idea is that recursion is absolutely essential to the human brain, and it's a part of the fact that humans have larger brains than other species. In fact, one of the papers at the recursion conference was on recursion in other species, and it talked about how when deer look for food in the forest, they often use recursive strategies to map their way across the forest and back, and take little side paths that can be analyzed as recursive paths. So it's not clear, first of all that recursion is unique to humans, and it's certainly not clear that recursion is part of language as opposed to part of the brain's general processing.

He says Piraha doesn't have recursion and that he thinks recursion isn't essential to human languages (thus in contradiction with Chomsky theories), but that it's part of how the brain processes information.

joe_the_user2• 17 years ago

I took note of the whole passage. Everett defines the Piraha grammar as not having recursion. He claims that when the Piraha use recursion in their linguistic communication ("story telling") they are somehow doing it outside the Piraha language. But the Piraha language is defined by the usage of the Piraha, not by one or another codified grammars.

Nevins et al. (linked above) note that recursion takes multiple forms in multiple languages and there isn't even anything terribly unusual about the form it takes in Piraha, even if this is a form Everett cannot accept into the grammar.

wgj2• 17 years ago

Regardless of the completeness of the language, I was really stunned by the total lack - as characterized in the article - of natural human curiosity. Does anyone know whether this component of the story is accurate?

Semiapies• 17 years ago

Pretty much every component of this story is being filtered through the claims of one man, a man who's one of only two known outsiders who speak their language to any extent - and according to the other person, not very well. Think how very weird you could make any group of people seem to another if you were the only person who could translate between them.

These people have no art, but they make impromptu sculptures with moving parts and decorative necklaces. They have no use for change and reject all things of the outside world, except for clothing, cloth, thread, machetes, movies, and random strangers, including families who hang around for decades trying to learn their language. They don't point...except maybe with their chins. Their language is strange and unusual - unless it's in a way that casts doubts on Daniel Everett's understanding, like Keren Everett's claims about prosody.

We don't know what these people are saying to Everett, and we have no idea what he's saying to them, due to either deception or a language barrier. Skepticism strikes me as entirely appropriate.

wgj2• 17 years ago

Thanks. That's really what I was thinking but I don't have the background to know.

nuncanada• 17 years ago

My spouse, being a scientist, watched one of his presentations and was astounded by the lack of real examples that would support Everett's world changing (in Linguistics) thesis. If he has made so much effort to try to convince others, why hasn't yet simply recorded enough data to support it?

ars• 17 years ago

This will sound bad, but did anyone check if they are the same species as other humans? (Not sure if species is the right word.)

According to the article they have been isolated for thousands of years.

Perhaps they don't have the same DNA for language as other humans do. Wikipedia said they don't have the ability to count, even when taught.

jimmyjim• 17 years ago

>Wikipedia said they don't have the ability to count, even when taught.

http://fora.tv/2009/03/20/Daniel_Everett_Endangered_Language...

In this interview, Everett mentions that he met a 13 year old girl in Brazil who happened in fact to be a Pirahãn—working as a cashier clerk, fully well able to count and do maths.

ytinas5• 17 years ago

The children can learn to count. The issue is reaching the age when your brain stops forming new connections without having language for certain concepts. If you lack the language to describe something you can't understand it. The only way an adult understands new concepts is in terms of previously known ones.

newhouseb• 17 years ago

I was talking to a friend and they said that in order to quantify objects this tribe counts on a logarithmic scale and not an ordinal one, which I found quite cool, since there's really no reason why we must count in one or the other (logarithmic or ordinal).

This seems counterintuitive at first, but logarithms are just ratios and henceforth sometimes actually more useful than ordinal counts - for example, when comparing say, land mass sizes and one plot is 1sq mi larger than the other. Without the context of the size of the plots, this is relatively useless (if they are huge, they're about exactly the same, if one is small then the other is massively bigger). If we say plot B is 1 log unit larger than plot A then it is twice (if base 2) bigger than plot A, no extra context required.

I thought it was cool...

gphil• 17 years ago

There is an episode (entitled "Numbers") of WNYC's Radiolab (available for free as a podcast at http://www.wnyc.org/shows/radiolab/) that talks about the possibility of an innate ability in infants to interpret quantities on a logarithmic scale, which is later supplanted by the ability to count ordinally. I haven't looked into how much evidence there is to support this theory, but the anecdote offered in the podcast is thought-provoking.

elblanco• 17 years ago

I actually came here to post the same link but you beat me to it! I also remember seeing some of the research related to humans estimated comparisons between two things, and that we naturally use a logarithmic scale to do this...but I couldn't remember the details of the paper.

yannis• 17 years ago

It is surprising, but the human brain is wired to think logarithmically, it is only by years of training that our brains get re-wired to do otherwise. Stanislas Dehaene has done a lot of research in this area (http://en.wikipedia.org/wiki/Stanislas_Dehaene). The study of how the brain interprets continuous and discrete signals (for example sound and numbers) has led to the discovery that the neural representation of number is comparable to the slide rule calculators, which was also graduated with a logarithmic scale. See (http://www.unicog.org/publications/Dehaene_WeberFechnerNiede...)

It is very efficient to do calculations logarithmically and evolution appears to have optimized our brains (and that of a few other animals) in this respect.

stcredzero• 17 years ago

It is surprising, but the human brain is wired to think logarithmically

Then again, we perceive forces, brightness, and loudness logarithmically. (This is not just the subjective experience. The way we are wired to our sound, light, and kinesthetic receptors is indeed logarithmic.) Why shouldn't we also naturally think that way?

scotty79• 17 years ago

Maybe this tribe has small mutation in FOXP2 gene causing impairment in comprehension of typical human grammar.

EDIT:

Maybe not.

> Gordon ruled out mass retardation. Though the Pirahã do not allow marriage outside their tribe, they have long kept their gene pool refreshed by permitting women to sleep with outsiders.

Unless this mutation is dominant.

> A Pirahã child removed from the jungle at birth and brought up in any city in the world, he said, would have no trouble learning the local tongue.

I wonder if they tried that.

jcl• 17 years ago

See jimmyjim's comment below:

http://news.ycombinator.com/item?id=1034232

mbuckbee• 17 years ago

Dan Everett is a pretty engaging speaker, you can listen to a talk he gave at the Long Now Foundation:

Talk Description:

http://www.longnow.org/seminars/02009/mar/20/endangered-lang...

Direct MP3 Link:

http://foratv.vo.llnwd.net/o33/mp3/2009-03-20_everett-LNF-16...

zandorg• 17 years ago

At University, my degree thesis was about an editor. You type in simple text phrases and it tries to parse, and if it can parse, displays the results in the bottom half of the editor window. This way you can write a database in plain English (eg, 'The cat is green') while making sure it's parseable too. You know it's parseable because the bottom window makes sense (it shows Prolog predicates - is_green[cat] )

It's just a UI concept, but something I've never managed to get finished.

Pirahã: a non-Turing-complete human language

Related Stories