So, I'm from Guatemala. This is a public service announcement that is where Guatemala is. Also, that is not where they keep the prisoners. That is called Guantanamo. Not the same place. So Guatemala is right below Mexico. And for the Americans in the audience, and let the sink in because it really applies in most ways. Americans in the audience, you can think of it as Mexico's Mexico. Just like the US doesn't want illegal immigration from Mexico, Mexico doesn't want illegal immigration from Guatemala. It's a smaller country. It's a poorer country. And well, what can I tell you? It has much better Mexican food.
Guatemala is a very poor country. And a lot of people talk about education as something that brings equality to different social classes. But I always thought it was the opposite, as something that brings inequality. Because what happens in practice is that people who have a lot of money can by themselves be really good education and therefore continue having a lot of money. Whereas people who don't have very much money, barely learn how to read and write. And therefore never make a lot of money. And this is especially true in poor countries. Now, I was fortunate that I received a rich person's education, even though I didn't grow up rich. And it's because I'm an only child. And my mother, who was a single mother, spent all of her resources on my education. And this allowed me to come to college to the US and eventually get a PhD in computer science.
Now, because of all of this, about 10 years ago, I decided I wanted to do something that would give equal access to education to everyone. Oh, by the way, this is what I want to talk to you about today. Giving equal access to education to everyone. At the time, I was a professor of computer science at Carnegie Mellon University. And I decided to work on this with my PhD students, Severing. The way my brain works, all of education is just too general of a problem. So I decided, let's start by teaching one thing. And then I started thinking, okay, well, what should we teach first? Should we teach math? I mean, we both love math. Me and my co-founder, we both love math. And we didn't decide to do math. And we started thinking, well, maybe we should teach computer science. But eventually, and this may be surprising to people in North America, eventually we decided that the best subject to start with was teaching foreign languages.
And let me tell you why. There's a number of reasons. One of them is that there's a huge audience for it. There's about two billion people in the world learning a foreign language, both in school and outside of schools. Most of these people, by the way, are learning English. About 80% of them are learning English. In this weird map right here, all the countries in green are countries in which people are predominantly learning English. And the reason for that is because English can truly transform your life. In most countries in the world, knowledge of English can significantly increase your income potential. So this is another reason why we decided to start with foreign languages. And it's because we can directly make more money if you learn another language in particular English.
And see, this is pretty different than many other subjects. For example, take math. In the case of math, just knowledge of math does not increase your income potential. Because usually you have to learn math to then learn physics to then become a civil engineer. Like that's how you make more money. Whereas with languages, if you are a waiter and you learn English, now you can be a waiter at a hotel and make more money. So we decided, well, let's get started by teaching languages. Now, we also convinced ourselves that the only way to really reach a lot of people was by using a mobile phone or a smartphone in particular. See, building schools all over the world is simple, too expensive. On the other hand, most of the world's population already has access to a smartphone.
And the trend is that that fraction is only going to increase. So we decided at the time that we would make a way to learn foreign languages on a mobile phone that was accessible to everyone. And then we called it Duolingo. Thank you. Now, in order to truly be accessible to everyone, rich and poor, Duolingo uses a freemium model to support itself. What that means is that you can learn as much as you want without ever having to pay. But if you don't pay, you may have to see an ad at the end of a lesson. Now, if you don't like ads, you can also pay to subscribe to turn off the ads. And it turns out that the vast majority of the revenue for Duolingo comes from people to pay to subscribe to turn off the ads.
Now who are these people who pay to subscribe to turn off the ads? Well, they're usually people, well off people, in rich countries like the US and Canada. Who are the people who don't pay to subscribe? They usually come from poorer countries like Brazil or Vietnam or Guatemala. So what I like about this model is that it is a small form of welfare distribution because we're basically getting the rich people to pay for the education of everyone. So I like that. Yes. It's a great. So with smartphones, we can reach a lot of people and we can even get the rich people to pay for the whole thing. This is great.
However, if you're trying to deliver education with a smartphone, you run into a humongous problem. And it is that smartphones come equipped with some of the most addictive drugs that humanity has ever engineered. TikTok, Instagram, mobile games. See delivering education over a smartphone is like hoping that people will eat their broccoli. But right next to it, you put the most delicious dessert ever made. If you really want to deliver education to everyone, not only do you have to make it accessible, but also you have to make it so that people want to actually learn. And we do a thing that we've been able to do this. And at the highest level, the way we've done this is by making the broccoli taste like dessert. I'll say it another way.
What we've done is that we've used the same psychological techniques that apps like Instagram, TikTok, or mobile games used to keep people engaged. But in this case, we used them to keep people engaged with education. Let me give you some examples of these techniques. One of the most powerful ones is the notion of a streak. What a streak is, is it's just a counter that measures the number of days that you've used the product consecutively. You just take that number, you put it very prominently in your product, and then people come back every day. And the reason people come back every day is because, well, if they don't come back, that number resets to zero, and people don't want to lose their streak. It works. Now, on the one side, streaks have been criticized for, for example, getting teens addicted to Snapchat. But in the case of an educational app, streaks get people to come back to study every day.
Now to give you an idea of the power of streaks, in the case of Duolingo, we have over 3 million daily active uses that have a streak longer than 365. That means they haven't missed the day in the last year or longer. Now, fun fact about streaks. What country do you think has the longest average streaks for an educational app? It's Japan. Of course. Shortest average streaks? Latin America, baby. But we're fun. We're fun. Another important mechanism to get people to come back to your product are notifications. On the one side, notifications can be really spammy and annoying. But in the case of an educational product, people actually want to be reminded to learn. In the case of Duolingo, we have a very sophisticated AI system that basically chooses when to send the notification and also what to say in each notification to maximize the probability that people come back. Interestingly, even after all, the sophistication, it turns out that the algorithm for choosing what time to send your notification is pretty simple. You know what is the best time to send people a notification? I'll tell you. It's 24 hours after they use the product last. Because there's an easy explanation. If you were free yesterday at 3 p.m., you're probably free today at 3 p.m. as well. So this is what a very sophisticated millions of dollars of AI found. It's funny.
Now with notifications, you shouldn't be spammy. And we're not spammy. We do a lingo. We actually stop sending notifications after seven days of inactivity. So if you don't use Duolingo for seven days, we stop sending notifications. Now at some point, it occurred to us, if we're stopping the same people notifications, we should let them know. So we started sending this notification to people saying, hey, these reminders don't seem to be working. We'll stop sending them for now. You know what people do when they get this notification? They come back. It's aggressive. Works for my mother. Works for Duolingo. These passive aggressive notifications are really good at getting people to come back because they feel like our green owl mascot has given up on them. So they come back and speaking of our green owl mascot, by the way, because all our notifications come from our green owl mascot and, well, he's passive aggressive and also pretty pushy, this is given rise to a lot of memes on the internet that make fun of just the great lengths that he will go through to get you back to learn a language. Here's one of my favorite ones. This is a meme. It's one of my favorite ones. It's basically looks like you forgot your Spanish lessons and then there's an intruder learned presumably the owl broke into your house to get your learn language. Now Duolingo has entered the site, guys, and there's thousands of memes. There's SNL skits about it. It's because we've managed to get people to want to learn a language by using the same techniques that mobile games and social media use to get people engaged. And this is a really important point.
Let me say this. I don't actually believe that there's a way to make an educational app as engaging as something like TikTok or Instagram or mobile games. But the good news is that, and by the way, the reason I don't believe that is because ultimately you have to teach people something and it's hard to compete with cats and celebrities. But the good news is that I don't think you have to. See, here's the thing. When you're learning something, you get meaning out of it. Whereas when you're scrolling for two hours on Instagram, a lot of times afterwards, you feel like you just wasted your time. So I think it's actually okay if your educational product is only 80 or 90% as engaging as something like TikTok because the other 10 or 20% will be provided by people's internal motivation. Though, of course, not much more than that. This is really a key point. If you want to get people to do something meaningful, you can use the same techniques that apps like social media use to get people to do it. And even if you're not as engaging as those apps are, you can still get hundreds of millions of people to use your product. In the case of Duolingo, for example, there are more people learning languages on Duolingo in the United States than there are people learning languages across all US high schools combined. And this is true in most countries in the world. My hope is that – I know we can do this – but my hope is that as humanity, we can do what Duolingo has done for learning languages, but for all other subjects where we can get people to learn math with mobile phones, like millions of people to learn math with mobile phones or physics or whatever. I hope for a future in which screen time is not a bad thing in which we can deliver high quality education to everyone, richer for using a mobile phone.
But the single most important thing that I can end this talk with is a reminder to please, pretty please, I beg you to your language lessons today. Thank you very much. Thank you. Thank you. Luis, thank you so much. Thank you. I wonder if you can just say a little bit more about that last point, about how do you think that you can apply this type of thinking to other subjects? So you mentioned math, you mentioned things like that. How do you do that? Yeah, I think in particular subjects that are learned through repetition. And it turns out most things that are kind of really meaningful to learn through like thousands and thousands of repetitions, you learn to read through repetition, you learn elementary school math repetition. Most things that you can learn through repetition, you can actually gamify and turn into something like Duolingo where people just do it a lot and do it fun. It's a little harder for things like explanations. That's probably going to require some really good videos. Salkan is doing a really good job with that. But for things that require a lot of repetition, I think we can use the same methods. Amazing. Thank you so much for sharing with me. Thank you. Thank you.