Hi Reddit! It’s me again, Luis von Ahn. I’m the co-founder/CEO of Duolingo, which aims to provide the best way to learn languages to everybody for free. I think that education makes people’s lives better, and shouldn’t be limited only to those who have the money to learn.

Today I’m especially excited because we just launched the Duolingo Android app. You can download it from Google Play here. If offers full language courses that are 100% free, with no ads, hidden charges, or BS “in-app purchases.”

You may be interested to know that there’s an awesome Duolingo subreddit.

I'm also a computer science professor at Carnegie Mellon, and I'm from Guatemala. I developed CAPTCHA and reCAPTCHA (acquired by Google).

Picture proof!

I'll start at 2pm ET, so ask away!

UPDATE [4:45pm]: Still hard at work answering your questions. Getting some help from my top advisor, Coco: http://imgur.com/fGNi1hy

UPDATE [7:30pm]: Taking a little break. I'll come back online later tonight to answer a few more questions :)

Comments: 1499 • Responses: 58  • Date: 

Noobleton551 karma

Forgive my ignorance if this is easily googled, but how does Duolingo make enough money if it's free and has no ads?

TangoZippo888 karma

People pay to have their documents crowd-translated.

vonahn781 karma

This :)

estrellaguate469 karma

Just wanted to thank you Luis for Duolingo. We use the English program at our orphanage in your home country of Guatemala for our children. They love it! We have a few kids who are bilingual, English/Spanish and are checking out other languages too, but we have one who is waiting from Mandarin.

vonahn394 karma

This made our day here in the office!

ken27238458 karma

To continue this AMA please enter the following:


vonahn550 karma

OVERLOOKS (you only have to type one correctly!)

ken27238409 karma

So you're telling me I only have to enter one?!?! I've been entering both.

My life is a lie....

vonahn504 karma

But you gotta know which one of the two to enter!

ComplimentsYou_147 karma

I use to be really good at guessing which of the two I needed to enter, I can't do it as frequently anymore though...

Did something change?

vonahn564 karma


bgsain404 karma

I love Duolingo, however, it got a bit creepy on me the other day...


jridenoure227 karma

yeah, I got this about a week ago.

vonahn452 karma

There's actually a pretty great Twitter account dedicated to the more peculiar Duolingo sentences. We think they give it character! :)

LoopOfPoop69 karma


vonahn294 karma

I just noticed your username. Not creepy either.

vonahn277 karma

Yeah, how is that creepy? Cmon.

archaeo-nemesis325 karma

I'm a big fan of Duolingo, but I'm curious about one thing: do you have any reservations about allowing language students (non-native speakers) to do official translations of online text? I understand that this arrangement keeps Duolingo services free, but do you ever worry that student-translated text will be inaccurate?

vonahn436 karma

We do worry about that, but it turns out it's very accurate. In fact, in all the studies we do, we find that the final translations from Duolingo are as accurate as those from professional translators.

Gehalgod264 karma

crappy language learning software

What exactly are the reasons that you find most language learning software deficient, and how does DuoLingo make up for these shortcomings?

vonahn605 karma

Because they don't motivate you to keep going! We spend a lot of effort making Duolingo addictive -- we think the hardest part about learning anything on your own is motivation.

Mojonator249 karma

Next year for April fool's can you put up Klingon and Jibberish as options?

vonahn314 karma

We tried to do it this year, but then got sidetracked by working on the Android app :(

MrXhin183 karma

Can you add Russian? There's this girl at work whose pants I want to get into.

vonahn294 karma

This is the single most compelling reason I've heard to add a new language. Hang tight bro, we'll help you out.

Archenim149 karma

Thanks for doing the AMA. I am a big fan of Duolingo. How many languages can you personally speak?

vonahn419 karma

I'm perfectly fluent in English and Spanish. Learning Portuguese, and failed at learning French in high school (though, in my defense, I only took it cuz I had a crush on a girl).

Archenim138 karma

I'm doing the German course on Duolingo right now, this is when terms like "Hosen aus!" come into handy.

vonahn263 karma

Pants off! One of the most useful phrases you'll ever learn.

juckele41 karma

Did you ever go on a date with said girl, or use your poor performance in the class to set up sly tutoring lessons?

vonahn244 karma

It turned out half the French class was also there because they had a crush on her! We've been looking into hiring her to convince people to learn French on Duolingo...

ssn136 karma

Who inspires you?

vonahn658 karma

Ron Swanson.

newyankee134 karma

Hi , do you think there is a way to gamify the creation of subtitles for any internet video based on web standards? I ask you this because this can make any content engaging for a large group of people as well as significantly improve the accessibility of web for many people.

vonahn124 karma

We discuss this idea often inside the team. We definitely will do it at some point, but we've been busy working on other stuff, such as our Android app :)

KennyEvil122 karma

Are there any plans to integrate student to student video calls or to partner with a website that provides this service? I find that I can now read quite well in French, understand spoken French but it falls apart when I try to speak it.

(Ps thanks for the site. Currently on Level 7 Spanish, Level 2 Italian and Level 14 French)

vonahn298 karma

We've thought about this a lot, but there are two problems we can't seem to shake off: (1) People just aren't that good at teaching languages to each other when they don't speak the same language, and (2) It is really hard to create an experience that won't be creepy (the last thing we want is for it to become plagued by penises like Chatroulette...)

EatMyBiscuits326 karma

What if you made face-to-face learning only available after a certain amount of levels? That way the service isn't open to opportunistic flashers, and the people who it is open to already have an investment that discourages bad behaviour. You could also have a confidence rating for each user who want to use this part of the service, like eBay buyer/seller ratings.

vonahn292 karma

This is not a bad idea.

kindall11 karma

plagued by penises

Dibs on this as a band name.

vonahn21 karma

Remember me when you're famous.

RollerDoll115 karma

Any plans to upgrade the Android app to add screen rotation? My Samsung Galaxy has a pull-out keyboard and I have to hold it cock-eyed to use the app.

vonahn179 karma

Yes! We'll be adding landscape mode in a couple of weeks.

rhythmkeeper96 karma

Are there any new languages planned for Duolingo coming up?

vonahn268 karma

Adding new languages is a difficult and time consuming task. We have a small team, and we’ve realized we’ll never be able to add all the languages we want as fast as we want. That said, we get a lot of emails from people who really like our cause, are interested in learning Dutch, Swedish, Turkish (you name it!), and want to help us add more languages. So that’s the approach we plan to take: Instead of us slowly adding languages, we’ll create all the tools necessary for the community to build them. This means we can introduce more languages and empower other experts and people passionate about a specific language to lead the way.

We don’t yet have a date for when this will go live, but it’s on the roadmap.

watchingmidnight32 karma

Are you still planning on releasing any languages from duolingo directly, or is the effort all going into making it so other people can add languages?

vonahn80 karma

All effort is going into making it so other people can add them. Adding languages by ourselves doesn't scale.

micahherstand32 karma

Crowdsourcing translations (and eventually instruction) seems like it'll be great on average, and even statistically significant in its positives, and yet it would seem that negative outliers are inevitable that just wouldn't happen when dealing with experts. Do you have plans to account for this?

vonahn54 karma

Yes, we do. This is what we worry about all the time, but we think we have enough good-willed people (like yourself) that good will prevail.

rmsy89 karma

What are your plans to promote Duolingo within the K-12 education world? It's desperately needed, and it's a perfect fit.

vonahn108 karma

We have several thousand students using Duolingo in classrooms all over the world, but it's all been organic. We haven't done much to promote its use in schools because we don't have the resources to lobby school districts or governments.

MyNameIsFuchs73 karma

First: I'm a huge fan of DuoLingo (DL). Thank you for this awesome project.

  1. What is the long term goal (future) of DL? How is DL going to try to make money? With just the translations? Are you waiting to be aquired?
  2. Given that DL is free and only wants you to translate web pages: Why is DL not open sourced? Why is there no good API for it?
  3. When can we see Chinese for DL?
  4. Given you're the CEO of DL, how much time do you still have to do "pure" academic research?
  5. Given that at universities only really care about how many papers (and their significance) you publish, do you have some kind of special arrangement with Carnegie Mellon? You don't seem to publish too much, many professors would get into trouble.
  6. What is future plans? Go full time for DL or become a Full Professor? Any new revolutionary projects in you head?

To follow up:

I'd really love to see this become open source. I think people are quite eager to help and contribute to a project like this. I certainly would. You can also see what happens when you provide an extensive API... You guys wouldn't even have to spend time on an Android app. People would just come up with a handful of them and you could focus on other things.

Also: Can't wait for the tablet edition of the Android app. If you need a beta tester, send me the apk. :)


vonahn246 karma

What is the long term goal (future) of DL? How is DL going to try to make money? With just the translations? Are you waiting to be aquired?

We're definitely not waiting to be acquired. Our goal is to really have the best language learning site in the world and at the same time keep it totally free. In order to do that, we need to make enough money from the translations to support our operations, but we're pretty confident we can do that.

Given that DL is free and only wants you to translate web pages: Why is DL not open sourced? Why is there no good API for it?

Open-sourcing something well requires quite a bit of effort (it's not just about putting the code out there). We've considered this, but so far it has never been our top priority. Same goes for the API.

When can we see Chinese for DL?

As soon as we start allowing people to add their own languages, which will hopefully be some time this year.

Given you're the CEO of DL, how much time do you still have to do "pure" academic research?

Right now, zero. DL takes up quite a bit of time,

Given that at universities only really care about how many papers (and their significance) you publish, do you have some kind of special arrangement with Carnegie Mellon? You don't seem to publish too much, many professors would get into trouble.

I've been very fortunate that CMU has given me the freedom to do whatever I want, which happens to be building things like reCAPTCHA and Duolingo.

What is future plans? Go full time for DL or become a Full Professor? Any new revolutionary projects in you head?

I want to finish watching Gossip Girl.

Coffeeey66 karma

Is Duolingo actually making enough money the way it works now?

vonahn438 karma

The other day we found a quarter under the couch. I think that's the entirety of our revenue so far.

Inclement_Weathers56 karma

Duolingo user here. Great software! How long did it take to perfect the user interface? Is there a design or software you used as inspiration?

It's...really damn good.

vonahn72 karma

We have amazing and obsessive UI/UX designers who are very critical of their own work. It took about 1 year of work before we were happy enough with something to launch it.

metalshark50 karma

You appear to be very intelligent. How did you decide on your current path in life? When did you decide? Was it a deliberate decision or did you just find that taking advantage of random events led you to where you are today? Duolingo is awesome by the way. I'm patiently waiting for Mandarin and Japanese.

vonahn56 karma

These are hard questions to answer. I think most of what I've done has been at least 50% luck (being at the right place at the right time).

niting47 karma

Apart from languages, do you think there are other things that can be taught using the techniques involved in Duolingo?

vonahn116 karma

Yes, we think programming could be taught this way, but we're not actively working on it.

herzkolt29 karma

Oh I'd love something like that.

Just so you know, Duolingo is really of great help. I started to learn german on it when I decided to go on exchange, "until I could find a teacher". I couldn't find one in my city, so I have to travel every weekend. Duolingo helps me the rest of the week, and everything for free... You are amazing, thank you.

vonahn38 karma

Thank you! Hearing this really motivates us.

CapslockEngaged12340 karma

First of all, I really enjoy the site, and am glad that someone is taking strides to make language learning more enjoyable and affordable. I'm hoping it will put scams like Rosetta Stone out of business (not likely, but I can dream).

My question is regarding the method of teaching. I understand that the site is dependent on translations for revenue, but many people (including myself) believe that translations can be harmful in language learning after a certain extent. It is important to create your target language as a separate entity in your mind, rather than entangling it with English. Also, how do you plan to incorporate languages that are almost impossible to directly translate? I feel like the current model has limited itself to its current offerings (the romance languages and German. Although Scandanavian languages could work.)

For example, the direct Russian translation of the formal "hello" is "Be healthy!" These kinds of things are all over the language. I imagine it is even worse for east Asian languages like Mandarin and Japanese, which are among the most popular for learners.

Any comment on this method of teaching and its incorporation into languages that aren't necessarily translatable to English?

Keep up the good work!

vonahn218 karma

When we started Duolingo, we didn’t know much about how to best teach languages. So we read a bunch of books on how to do it, and we also talked to language acquisition experts, asking them very specific and practical questions. For example, I wanted to know, in Spanish should we teach adjectives before adverbs or adverbs before adjectives. And I was surprised to find out that they actually didn’t know the answer! They would say stuff like, “Well, the current philosophy is blah blah”, but never really get to the point. Nobody could tell me, for a fact, what was better. At first, I was pretty amazed and thought: “What the hell are these people good for?” But then I realized: I’m a computer science professor, and I can’t tell you what the best way to teach computer science is. I know how I do it and what has worked for me in the past, but that’s about it. And in fact, that’s basically the current status within most of education: we teach based on very little science.

So, we designed an initial curriculum based on everything we learned through reading books and asking experts. But then we realized something. As Duolingo started growing, we had a unique opportunity. We had millions of users and we could actually find out by ourselves everything we wanted to know. Questions nobody had ever answered before! So this is what we do now. We’re basically doing very large-scale data-driven education, and improving it every day. For example, if we want to know how early we should teach plurals, we simply test it. We give a group of 50,000 people plurals a little earlier in the course than everybody else, and we measure: do these people learn faster, do they learn better, do they stick around for longer? And if it’s better, we start teaching plurals earlier to everybody. This approach improves the experience on Duolingo and also is giving us answers to those language questions we really couldn’t find answers to when we were just starting out.

We will likely by adding other ways of learning the language but in all cases we'll be driven by the data we gather.

supermasenko39 karma

What inspired you to start duolingo?

Which languages will be added in the future?

Are there any new features planned?

Btw, thanks for duolingo I have never had so much fun learning Italian

vonahn197 karma

About three years ago, I was in a very fortunate position in my life. I had just sold my second company to Google, and I didn’t need to work anymore. Something that I’d always wanted to work on was education. I’m a professor and it’s a passion of mine, so I wanted to do something related to it. But see, my view was also colored by where I’m from. I was born and raised in Guatemala, which is a very poor country. So I wanted to make a system to provide free top-notch education to anybody, regardless of whether they can afford it.

riklemon34 karma

Are you friends with Salman Khan of the khan Academy? Was he an influence? Do you share ideas?

vonahn67 karma

I wouldn't say we're friends, but we've met. I love what they're doing.

vonahn34 karma

olimo32 karma

Are the sentences for the lessons computer generated? With all those mistakes and awkwardness wouldn't it be better to get them written by people, maybe even crowdsourced?

vonahn82 karma

Hi Olimo :) They are written by people! Maybe we should have them solve a CAPTCHA before they can write them.

BearcatChemist31 karma

I am currently using Rosetta Stone to learn Polish. How can you convince me that Duolingo is better? I have tried other stuff before, and always ended up wasting my time.

I understand trying it would work, but besides that. In other words, what does Duolingo have that Rosetta Stone doesn't?

vonahn99 karma

First, Duolingo is totally free. No ads, no subscriptions, no 5-easy-payments plan. Rosetta Stone costs hundreds of dollars.

Second, there is scientific evidence that Duolingo can be more effective. An independent study was done by a research team that previously evaluated the effectiveness of Rosetta Stone. They found that it takes students on Duolingo 34 hours to learn the equivalent of a one-semester university course, whereas it takes 55 hours with Rosetta Stone. Here is a link to the study: http://static.duolingo.com/s3/DuolingoReport_Final.pdf

And of course there are other differences that are harder to quantify: Duolingo has game mechanics, a 5-star mobile app, and since it doesn't come in a CD-ROM, we're able to improve it on a daily basis.

RealJSwole24 karma

How soon would you see Mandarin coming to DuoLingo?

vonahn27 karma

We'll be letting people add their own languages, so I assume pretty soon after that.

stonehengee24 karma

Very excited for the android app. Just wondering when it will be available for tablets? (I have a Nexus 10)

vonahn35 karma

We're hard at work on tablet support and it will be out in a few weeks. We just wanted to get the phone-optimized version out to people as soon as possible.

throwthisaway199123 karma

How did you figure out the CAPTCHA method for verification?

I'm not asking sarcastically or anything, I'm genuinely curious as to what the thought process behind it was.

penis_lad_man21 karma

I love duolingo! I do have one question though: what's your policy on it being used for a class?

I am in a Spanish class with a younger professor from Spain and showed him duolingo one day after class. He loved it more than our textbook software (ilrn-heinle) and wanted to find a way to incorporate it into his classes. I was just curious if you would allow this sort of thing or if you guys were looking to change the program to be an out-of-class aid for instructors in schools/universities?

More specifically, I would like to imagine duolingo having an option for instructors for them to find all their students and having it as a dropdown box on the side that's separate from their facebook or google+ firends. They can see their tokens and proficiencies in different areas and can then address this in class. Do you think this is in the future of duolingo?

Thank you for doing the AMA! I love your website and reccomend it to everyone I can!

vonahn53 karma

Dear penis_lad_man: Yes, we plan on adding this feature before September!

Series_of_Accidents20 karma

I also developed CAPTCHA and reCAPTCHA, those squiggly characters all over the web

You... It was you! evil bastard

vonahn15 karma

reCAPTCHA is for a good cause!

kaizeny19 karma

A lot of people think, that Duolingo is only for vocabulary. Do you think that's true?

riklemon60 karma

I don't agree, it introduces grammatical concepts bit by bit. It goes way beyond lists of vocab and tourist language. Actually, I think it would be great if it added more 'lists' of vocab to learn as an add-on to the units that already exist. So you could choose extra, more specialist lists of vocabulary relevant to a hobby or employment sector, or even draw up your own lists which the site would help you to memorize using its existing structures.

vonahn48 karma

I agree wholeheartedly with this :)

AlexTDS16 karma

What kind of success stories have you heard from people who have been using Duolingo ?

vonahn74 karma

It always feels good to hear from our users about how they passed a test that lets them save money on college courses, or showing us how much they have improved in their target language. But my all-time favorite was a bit of feedback we got from a user in Syria, who said "Living in a country torn by hideous civil war and daily terrible news can be unbearable, but Duolingo really lifts up my spirit."

JoinTheRightClick16 karma

Thanks for helping me with my Spanish, I can now order food without getting laughed at.

vonahn65 karma

Yo Quiero Taco Bell :)

run_zeno_run15 karma

Aside from language translation, what areas/problems do you think are most ripe for the application of human based computation systems?

vonahn24 karma

Finding bugs in code!

olimo14 karma

How long before we have more efficient Discussions engine? I'm annoyed to see the same questions and suggestions appear again and again, but at the same time I understand their posters because it is easier to ask right away than to try and find the old threads.

I would gladly contribute to an FAQ if there was some place for it.

vonahn20 karma

It is pretty difficult to make sure that we never see the same questions or suggestions being repeated (even Reddit has this problem!). An FAQ is a great idea though, and would be great to be able to direct new users to. We'll work on it!

thisisradioclash12 karma

I've used Rosetta Stone (got it free through the military), but I really like Duolingo much better. I'm currently using it to refresh my Italian skills I haven't used in a very long time.

I have two questions:

1) Can you add an option to use it silently, ie not having to listen and translate? It would be much easier to sneak a session or two in at work, or use it while the kids are watching tv.

2) Some of the lessons should have "cheat sheets", like "Prepositions". That's difficult to learn via osmosis, or just guessing at the translations; and for visual learners it's really hard to get them straight without seeing all the options. (I've relied on language books I have at home, and it's been really helpful)

Edit to add: Damn it, I forgot to say thanks! Thanks!

vonahn19 karma

1) Can you add an option to use it silently, ie not having to listen and translate? It would be much easier to sneak a session or two in at work, or use it while the kids are watching tv.

It's there! Go to the settings :)

2) Some of the lessons should have "cheat sheets", like "Prepositions". That's difficult to learn via osmosis, or just guessing at the translations; and for visual learners it's really hard to get them straight without seeing all the options. (I've relied on language books I have at home, and it's been really helpful)

Agreed. We'll be working on this.

Edit to add: Damn it, I forgot to say thanks! Thanks!

Thanks! :)

djfun10 karma

Any plans for a mobile version of the Duolingo website for users of Windows Phone, Blackberry, Ubuntu Touch, Jolla Sailfish, ..?

vonahn60 karma

We're working on the Commodore 64 version first.

pridkett10 karma

Please say that you're going to do a TI-99/4a version after that. The speech synthesizer has got to be useful for something...

vonahn31 karma

First TI-83.

raisinsPeanuts10 karma

Hi Luis! First of all, you're my hero. Your work in CS and your commitment to making language learning free is so inspiring.

Second of all, what has Duolingo's growth looked like? (Did you have any big moments where you had explosions in # of users, when you realized that you really had something going with this company, etc)

vonahn10 karma

Thank you! :)

Duolingo has been growing non-stop since we launched last year. I'd say one major point was when we launched our iPhone app, and we're hoping the same happens starting today after launching our Android app.

iams3b10 karma

How many of the languages you provide do you yourself know? Do you hire people specifically to write translations for the courses or is there any auto-translating going on behind the scenes?

How do you break down how the courses are set up, for languages that you might now know?

vonahn20 karma

I know English and Spanish perfectly fluently, and Portuguese a little bit. We do hire people specifically for each language.

donliu7 karma

how do you split time between teaching/researching/doing startup and managed to be (pretty much) successful everywhere?

vonahn4 karma

This varies quite a bit. Right now I'm spending all of my time on Duolingo because I'm pretty obsessed with it.

[deleted]6 karma


vonahn33 karma

Duke. GPA? Who cares about GPA!

CapitanPeluche10 karma

I go to UNC, but your second sentence makes me immediately love you.

vonahn12 karma


c0rruptioN5 karma

You're on a roll! Whats the next big thing for you?

bradbeattie4 karma


vonahn8 karma


notsurehowtosaythis4 karma

Is there someway you can prove you aren't a bot answering questions?

vonahn5 karma

I can answer this: "1+1 = ?" It's 2!

elstompy4 karma

I've seen mention in the past that Duolingo was working on a way to "restart" a language or that lack of use would diminish progress on certain lessons and that you could then go back and build up. Being a few months away from Duolingo I would like to start over from the beginning without it incorporating words learned in later lessons, but seeing as I have friends and followers on Duolingo I don't wish to scrap my account and re-sign up with a new one. A couple of months ago it was mentioned you were a couple of weeks away from that. Any idea on when we can actually expect it. I know I'm far from the only one.

vonahn3 karma

We released the ability to do this 2 days ago! Just go to your settings :)