Reviewer: Anny Chung
Ok, so I want to start by asking a question:
How many of you have had to fill out some sort of web form
or even has to read a distorted sequence of characters like this?
How many of you found it really annoying?
Ok, I understand.
I invented that.
(Laughter)
Well, I was one of the people who did it.
That thing is called a captcha.
And the reason it's there is to make sure that you,
the entity filling out the form, are actually a human,
and not a computer program
written to submit the form millions of times.
The reason it works is because humans,
at least, non-visually-impaired humans,
have no trouble reading these distorted characters,
whereas computer programs simply can't do it as well yet.
For example, in the case of Ticket Master
the reason you have to type these distorted characters
is to prevent scalpers to write a program that can buy
millions of ticket at a time.
Captchas are used all over the Internet
and they are used so often that a lot of times
the precise sequence of random characters that are shown to the user
is not so fortunate.
This is an example from the Yahoo registration page.
[W A I T]
Random characters that happen to be shown to the user
were W, A, I, T, which of course spell a word.
But the best part is the message
that the Yahoo Help got about 20 minutes later.
["Help! I've been waiting for 20 minutes, and nothing happens!"]
(Laughter)
This of course is not as bad as this poor person who...
[R E S T A R T]
(Laughter)
Ok, now, this Captcha project was something that we did
here at Carnegie Mellon
about ten years ago and is used everywhere.
Let me now tell you about a project that we did a few years later,
which is sort of the next evolution of captchas.
This is the project that we called Recaptcha,
which is something that we started here at Carnegie Melon,
then we turned it into a startup company,
and then about a year and a half ago
Google actually acquired this company.
So, let me tell you [how] this project started.
So this project started from the following realization:
it turns out that approximately 200 million captchas
are typed every day by people around the world.
When I first heard this I was quite proud of myself
I thought, "Look at the impact that my research has had."
But then I started feeling bad,
see here is the thing: each time you type a captcha,
essentially, you waste ten seconds of your time.
Because it takes ten seconds to type a captcha --
and if you multiply that by 200 million you get that humanity as a whole
is wasting about 500 thousand hours every day
typing these annoying captchas. (Laughter)
So then I started feeling bad,
(Laughter)
and I started thinking, "Well, of course we can't just
get rid of captchas, because the security of the Web
sort of depends on them, but then I started thinking,
"Is there any way we can use this effort
for something that is good for humanity?"
Here is the thing, while you're typing a captcha,
during those ten seconds,
your brain is doing something amazing.
It is doing something that computers cannot yet do.
So, can we get you to do useful work for those ten seconds?
Another way of putting it is:
Is there some humongous problem that we cannot get yet computers to solve,
that somehow we can split into tiny ten second chunks
such that each time somebody solves a captcha
they solve a little bit of this problem?
The answer is yes, and this is what we are doing now.
What you may not know is that nowadays,
while you're typing a captcha
not only are you authenticating yourself as a human
but in addition you are actually helping us to digitize books.
Let me explain how it works.
A lot of projects are trying to digitize books.
Google has one, the Internet Archive has one,
Amazon, with the Kindle, is trying to digitize books.
The way is works is, you start with an old book, a physical thing,
you've seen those things right? Like a... book...
(Laughter)
So, you start with a book, and then you scan it.
Scanning a book is like taking a digital photograph
of every page of the book.
It gives you an image for every page of the book.
This is an image with text for every page of the book.
The next step in the process is that the computer needs to be able
to decipher all of the words in this image.
That is done using a tecnology called OCR,
Optical Character Recognition,
which takes a picture of text
and tries to figure out what text is in there.
Now, the problem is that OCR is not perfect,
especially for older books, where the ink has faded,
and the pages have turned yellow,
OCR cannot recognize a lot of the words.
For things that were written more than fifty years ago,
the computer cannot recognize about thirty percent of the words.
We are now taking all of the words that the computer cannot recognize
and we are getting people to read them for us,
while they are typing a captcha on the Internet.
So next time you type a captcha,
these words that you're typing are actually words
that are coming from books that are being digitized
that the computer could not recognize.
The reason we have two words nowadays instead of one,
is because one of the words
is a word that the system just got out of a book,
it didn't know what it was
and it's going to present it to you,
but since it doesn't know the answer for it,
it cannot grade it for you,
so we give you another word,
one for which the system does know the answer,
we don't tell you which one is which, and we say, please type both.
If you type the correct word
for the one which the system already knows,
it assumes you are a human,
and it also gets some confidence that you typed the other word correctly.
And if we repeat this process to ten different people,
and all of them agree on what the new word is,
then we have one more word digitized accurately.
This is how the system works,
and since we released it about 3 or 4 years ago,
a lot of websites started switching from
the old captcha, where people wasted their time,
to the new captcha, where people are helping to digitize books.
So every time you buy tickets on Ticket Master,
you help to digitize a book.
Facebook, every time you add a friend,
or poke somebody, you help digitize a book.
Twitter, and about 350 thousand other sites
are all using recaptcha. And in fact, the number of sites
that are using recaptcha is so high
that the number of words that we're digitizing per day
is really large. It's about 100 million a day
which is the equivalent of about
2.5 million books a year.
And this is all being done one word at a time
by just people typing captchas on the Internet.
(Applause)
Of course, since we are doing so many words per day
funny things can happen, and this is especially true
because now we're giving people
two randomly-chosen English words next to each other.
So funny things can happen, for example,
we presented this word, it's the word "christians",
there's nothing wrong with it,
but if you present it along with another randomly chosen word,
bad things can happen:
["bad christians"] (Laughter)
But it's even worse because the particular website
where we showed this actually happened to be called
The Embassy of the Kingdom of God.
(Laughter)
Here is another really bad one:
johnedwards.com
["damn liberal"]
(Laughter)
So we keep on insulting people left and right every day.
Of course we are not just insulting people,
see, here is the thing, since we're presenting
two randomly chosen words,
just interesting things can happen.
So this actually has given rise to
a really big Internet meme
that tens of thousands of people have participated in,
which is called Captcha Art.
I'm sure some of you have heard about it,
here's how it works: imagine you're using the Internet
and you see a captcha that you think
is somewhat peculiar.
Like this captcha: ["invisible toaster"]
Then you take a screenshot of it,
-- of course you fill out the captcha
because it helps us digitize a book --
but then, first you take a screenshot
and then you draw something that is related to it.
(Laughter)
That's how it works.
There are tens of thousands of these,
some of them are very cute,
[clenched it]
some of them are funnier,
[stoned founders]
(Laughter)
and some of them, like "paleontological shvisle",
they contain Snoop Dog.
(Laughter)
Ok, so this is my favorite number of recaptchas
this is the favorite thing that I like about this whole project.
This is the number of distinct people
that have helped us digitize at least one word out of a book
through recaptcha: 750 million, which is a little over
than ten percent of the world's population
has helped us digitize human knowledge.
And it is numbers like these that motivate my research agenda.
The question that motivates my research is the following:
if you look at humanity's large scale achievements
these really big things that humanity
has gotten together and done historically,
like for example, building the pyramids of Egypt,
or the Panama canal, or putting a man on the moon,
there's a curious fact about them.
And it is that they were all done
with about the same number of people.
It's weird. They were all done with about 100 thousand people
And the reason for that is because
before the Internet, coordinating
more than 100 thousand people
let alone paying them, was essentially impossible.
But see now with the Internet,
I've just shown you a project where we've gotten
750 million people to help us digitize human knowledge.
So the question that motivates my research is
if we can put a man on the moon with 100 thousand
what can we do with 100 million?
So based on this question we've had a lot
of different projects that we've been working on,
let me tell you about one that I'm most excited about
this is something that we've been sort of semi-quietly working on
for the last year and a half or so.
It hasn't yet been launched, it's called Duolingo,
since it hasn't been launched, shhh!
(Laughter)
Ah, yeah, I can trust you....
Ok, so here is how it started:
it started with me posing a question to my graduate student,
Severin Hacker -- this clicker is not working so well --
ok that's Severin Hacker,
so I posed a question to my graduate student
by the way, you did hear me correctly,
his last name is Hacker,
so I posed this question to him:
how can we get 100 million people
translating the Web into every major language for free?
There's a lot of things to say about this question.
First of all, translating the Web.
So, right now the Web is partitioned into multiple languages,
a large fraction of it is in English,
if you don't know any English you can't access it,
but there's large fractions in other different languages,
and if you don't know those languages you can't access it.
So I would like to translate all of the web
or at least, most of it into every major language.
So that's what I would like to do.
Now, some of you may say,
why can't we use computers to translate,
why can't we use machine translation,
which nowadays is starting to translate some sentences here and there,
why can't we use it to translate the whole Web?
Well, the problem is, it's not yet good enough,
and it probably won't be for the next 15 to 20 years.
It makes a lot of mistakes, and even when it doesn't
since it makes so many mistakes you don't know whether to trust it or not.
Let me show you an example
of something that was translated with a machine,
it was actually a forum post with someone
who was trying to ask a question about Javascript.
It was translated from Japanese into English.
Let's see if this works.
I'll just let you read, this person starts apologizing
for the fact that it's translated with the computer.
[This is question, English is faulty. Thank computer to translate. Sorry!]
The next sentence is going to be the preamble to the question
he's just explaining something,
remember, it's a question about Javascript:
[At often, the goat-time install a error is vomit.]
(Laughter)
Then comes the first part of the question:
[How many times like the wind, a pole, and the dragon?]
(Laughter)
Then comes my favorite part of the question:
[This insult to father's stones?]
(Laughter)
And then comes the ending,
which is my favorite part of the whole thing:
[Please apologize for your stupidity. There are a many thank you.]
(Laughter)
Ok, so computer translation, not yet good enough.
Ok? So back to the question, we need people to translate the whole Web.
Now the next question you may have is
"Why can't we just pay people to do this,
we could pay professional language translators
to translate the whole Web".
We could do that.
Unfortunately, it'd be extremely expensive.
For example, translating a tiny tiny fraction
of the whole Web, Wikipedia,
into one other language, Spanish.
You know, Wikipedia exists in Spanish,
but it is very small compared to the size of English,
it's about 20% the size of English.
If you want to translate the other 80% into Spanish
it would cost at least 50 million dollars.
This is even at the most exploited outsourcing country out there.
(Laughter)
So, it'd very expensive. What we want to do
is to get 100 million people translating the Web
into every major language for free.
Now, if this is what you want to do
you pretty quickly realize you're going to run into
two pretty big hurdles, two big obstacles.
The first one is a lack of bilinguals.
I don't even know if there exists 100 million people out there
using the Web who are bilingual enough to help us translate.
That's a big problem.
The other problem that you're going to run into
is the lack of motivation.
How are we going to motivate people
to actually translate the Web for free?
Normally, you have to pay people to do this,
so how are you going to motivate them to do it for free?
Now, when we were starting to think about this
we were blocked by these two things
but then we realized that there's actually a way
to solve both these problems with the same solution.
There's a way to kill two birds with one stone.
And that is to transform language translation into
something that millions of people want to do
and that also helps with the problem
of a lack of bilinguals.
And that is language education.
So, it turns out that, today, there are over 1.2 billion people
learning a foreign language.
People really want to learn a foreign language,
and it's not just because they're being forced to do so in school.
For example, in the United States alone
there are 5 million people who have paid over 500 dollars
for software to learn a new language.
So people really want to learn a new language.
What we've been working on for the last year and half
is a new website.
It's called Duolingo.
Where the basic idea is
as people use Duolingo, people learn a new language for free
while simultaneously translating the Web.
Basically they are learning by doing.
The way this works is
whenever you're just a beginner we give you very simple sentences,
there's of course a lot of very simple sentences on the Web.
We give you very simple sentences
along with what each word means.
And as you translate them,
and as you see how other people translate them,
you start learning the language, as you get more advanced,
we give you more complex sentences to translate.
But at all times, you are learning by doing.
The crazy thing about this method
is that it actually really works.
First of all, people are really learning a language
we're mostly done building, and we are now testing it
people really can learn a language with it.
And they learn it about as well as the leading language learning software.
So people really do learn a language.
And not only do they learn it as well, but actually it's way more interesting.
Because, you see, with Duolingo
people are actually learning with real content.
As opposed to learning with made-up sentences
people are learning with real content,
which is inherently interesting.
So people really do learn a language,
but perhaps, more surprisingly,
the translations that we get from people
using the site, even though they're just beginners,
the translations that we get are as accurate
as those of professional language translators,
which is very surprising.
Let me show you one example, this is a sentence
that was translated from German into English
the top is the German,
the middle is an English translation
that was done by somebody who was a professional language translator,
who we've paid 20 cents a word for this translation,
and the bottom is a translation by users of Duolingo,
none of whom knew any German
before they started using the site.
As you can see, it's pretty much perfect.
Now, of course we played a trick here
to make the translations as good as
professional language translators.
We combined the translations of multiple beginners
to get the quality of a single professional translator.
Even though we're combining the translations
the site actually can translate pretty fast.
Let me show you, these are estimates
of how fast we could translate Wikipedia
from English into Spanish.
Remember, this is 50 million dollars worth of value.
If we wanted to translate Wikipedia into Spanish
we can do it in five weeks with 100 thousand active users,
and we can do it in about 80 hours with 1 million active users.
Since all of the projects my group has worked on so far
have gotten millions of users,
we're hopeful that we would be able
to translate extremely fast with this project.
Now, the thing that I am most excited about Duolingo
is that I think this provides a fair business model
for language education.
So here's the thing:
the current business model for language education is:
the student pays.
And, particularly, the student pays Rosetta Stone 500 dollars.
That's the current business model.
The problem with this business model
is that 95% of the world's population
doesn't have 500 dollars.
So it's extremely unfair towards the poor,
this is totally biased towards the rich.
In Duolingo, because while you learn
you're actually creating value,
you are translating stuff which, for example,
we could charge somebody for translation
-- this is how we could monetize this.
Since people are creating value while learning,
they don't have to pay with their money, they pay with their time.
But the magical thing here is that they're paying with their time
but that is time that would have to be spent anyway,
learning the language.
The nice thing about Duolingo is
I think it provides a fair business model,
one that doesn't discriminate against the poor people.
So, here is the site: [www.duolingo.com]
(Applause)
Thank you.
(Applause)
Here's the site. We haven't yet launched
but if you go there you can sign up to be part of our private beta
which we're probably going to start in about three or four weeks.
By the way, I'm the one talking here,
but actually Duolingo is the work of a really awesome team
some of whom are here.
So, thank you.
(Applause)