
Pirahã:  a non-Turing-complete human language - nwatson
http://www.newyorker.com/reporting/2007/04/16/070416fa_fact_colapinto
======
nwatson
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.

~~~
madair
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?

~~~
nwatson
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.

~~~
wjdix
It is not in fact impossible to express that sort of sentence in Piraha.
Embedding is accomplished by "noun-ifying" a clause by adding "-sai". The
debate is whether or not this suffix represents actual embedding/recusion.
This debate has been discussed at length in Language and other sources.

------
joe_the_user
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...](http://www.edge.org/3rd_culture/everett07/everett07_index.html))

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
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_user
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.

------
newhouseb
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...

~~~
yannis
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...](http://www.unicog.org/publications/Dehaene_WeberFechnerNieder_TICS2003.pdf))

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
_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
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
See jimmyjim's comment below:

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

------
RyanMcGreal
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.

~~~
ytinas
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....

~~~
RyanMcGreal
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.

~~~
ytinas
But they've been _exposed_ to other concepts, perhaps these new concepts don't
become important because they don't understand them. :)

------
wgj
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
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.

~~~
nuncanada
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?

------
zandorg
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.

------
mbuckbee
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...](http://www.longnow.org/seminars/02009/mar/20/endangered-languages-
lost-knowledge-and-future/)

Direct MP3 Link:

[http://foratv.vo.llnwd.net/o33/mp3/2009-03-20_everett-
LNF-16...](http://foratv.vo.llnwd.net/o33/mp3/2009-03-20_everett-
LNF-16x9-9262_download.mp3)

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

[http://fora.tv/2009/03/20/Daniel_Everett_Endangered_Language...](http://fora.tv/2009/03/20/Daniel_Everett_Endangered_Languages_and_Lost_Knowledge#fullprogram)

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.

~~~
ytinas
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.

~~~
ytinas
Does it not violate ycombinator etiquette to just vote someone down past 0
without explaining why? My comment wasn't remotely snarky, nor something I
wouldn't say to anyone's face.

~~~
jodrellblank
I don't think it does violate etiquette - although it's usually pretty obvious
that the comment being downvoted is not a good contribution, either in the
insulting or rude category, or in the unhelpful "lol, ++, good read, {joke
from TV show}" style.

I can only guess, but I wonder if yours was downvoted for making claims that
seem wrong without backing them up - I don't think there is an age when new
connections are no longer made nor do I agree that adults can only learn from
what they already know - but I wouldn't vote it down because of my
disagreement.

Though there has been recent discussion on people voting down purely for
disagreement, and that might well violate etiquette. But just <0 without a
comment doesn't necessarily do so.

~~~
ytinas
Well my mistake, I didn't realize this point was still under contention. I was
under the impression that it's common knowledge that new connections are not
created in the brain after a certain age (15-ish as I recall) and all new
connections must be formed from existing ones.

This is why e.g. bilingual kids learn new languages much faster than people
who only speak one language, people who learn an instrument as a child can
pick up new ones much faster, etc.

What _is_ a personal theory of mine is that if you don't have language to
understand a concept by a certain point you can never truly understand it. The
only places I point to that support my theory are the few cases of children
being raised away from humans [1] and this Pirahã story. It's pretty difficult
to prove scientifically since it would require destroying someone's life.

But on this site, of all sites, I would expect discussion about it, not a
simple down vote.

[1] I've heard of at least 2 seperate cases where through some odd
circumstanced a child reached teenage years without learning any kind of
communication with humans. After they were rescued, in both cases they were
never able to grasp concepts much further than a young child (around where
chimps who learn sign language get to). This is by no means conclusive, since
they obviously went through an incredibly traumatic experience, but as I
mentioned above, there is no easy way to apply scientific method to this
theory.

------
wjdix
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
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.

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

~~~
neilk
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.

