Nervous to Practice a New Language? Try AI, Duolingo Says

Duolingo, the "freemium" language app that teaches you in bite-sized, game-style portions, has been working on an AI tutor and forging ahead with its quest to use language skills as a means to lift people out of poverty. Ahead of its sixth birthday this week, PCMag dropped by its Pittsburgh headquarters to learn more.

HQ is in East Liberty, an up-and-coming part of the city, half a mile from Google's Steel City offices and 2 miles from Carnegie Mellon University, where cofounders Luis von Ahn (CEO) and Severin Hacker (CTO) both studied. Von Ahn is best known as the inventor of CAPTCHA/reCAPTCHA, a way of digitizing old books (which OCR programs have struggled to decipher) via human computation, which he sold to Google in 2009 for an undisclosed sum.

In the Duolingo lobby, a video wall shows a world map and hundreds of tiny colored beams which, powered by real-time data feeds, light up as individual language students start up a lesson.

It feels slightly intrusive knowing that "Emilio did an English lesson" in Ecuador, but it's also fascinating to see what languages people are learning around the world.

One of the more interesting ones on this list is High Valyrian, created by David J. Peterson, the linguistic expert behind Game of Thrones' constructed languages, who we interviewed in 2016.

"The High Valyrian project is nothing like I've ever done before," Peterson said via email. "Every bit of it was fascinating, but challenging. I had to create the curriculum, write almost every sentence, and familiarize myself with the UI of Duolingo's internal incubator. Three-fifths of the course has been released to the public so far, and the plan is to have it finished sometime next year."

Retro Tech Alert

Beyond the video wall, what's most noticeable about Duolingo's offices are the retro tech devices charging inside a simple wooden shelving unit.

Startups often pride themselves on the latest shiny new gadget, and catering to customers that can afford them, but as von Ahn explained, his mission is help the entire world learn languages for free, lifting people out of poverty. Duolingo needs to work—and well—on as many devices as possible.

Here are edited and condensed excerpts from our conversation.

Bom Dia! Heard you're using your own product to learn Brazilian Portuguese.
[Laughs] Yes, but very slowly. It's our second biggest market, you see.

Tell us more about the concept of democratizing language learning.
There are currently 1.2 billion people learning a language worldwide. Two-thirds of them satisfy three properties: They're learning English, they're doing so to get a job, and they are from a low socio-economic condition. But most of the ways to do that are very expensive, around five hundred bucks, so we strongly believe we need to give language education for free, in as much as we can.

English is the focus—but you offer many other languages now.
English is the big one that people need to learn, but yes, we're doing it for an increasing number of languages now.

Including High Valyrian.
Yes. David J. Peterson came to us because he wanted to create the course. It's been great. It does pretty well—even better, as you'd expect, when Game of Thrones seasons are out. It's pretty amazing.

Let's talk about the intelligence built into the app. We noticed when brushing up on Brazilian Portuguese that the lesson felt responsive, not formulaic or rote.
We spend a lot of time tweaking the model behind the product to know when to present new concepts to the user, and to track what they know already. We have so much data that we can posit a model that predicts what you'll do every time you do an exercise. If you get that right, our model is right. If you get something wrong, we update the model.

Sounds pretty sophisticated.
Yes. As a model, which is constantly learning, we can predict most outcomes—even knowing what level you'll have forgotten of that language based on the time you've been away and haven't done your lessons with us.

Talk about those charming little characters who offer encouragement and praise inside the app.
That's what we spend most of our efforts on today. When we initially launched Duolingo in 2012, of the people who signed up to do it, only 13 percent came back the next day. Today, due to the gamification, our knowledge of how to talk to learners, it's about 55 percent. We are constantly improving, not just the email reminder language that gets sent, but how the points system works, every aspect of the educational process—we're constantly refining it all.

Tell us about the language certification you're offering now.
It was based on user demand. People kept sending us emails saying, "Thank you for teaching me English, I wasn't able to afford it before now. But I have a problem because I need a certificate that says I can speak it."

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TOEFL and other types of certifications are expensive.
Right. We went and looked at the English language certification market and what we found was crazy. Firstly, it's worth $5 billion a year—that's what people spend on taking standardized tests to prove their language proficiency at about $250 per test—that's a month's salary in emerging economies. The process also takes six to eight weeks, which is too long if you're waiting for a certificate to get a job and it's required you go to a testing center, to prevent cheating, but these aren't in every city so you have to pay to travel, and take time off to get there.

A market ripe for disruption—and financially rewarding. What's your solution?
We decided to make our own test—Duolingo English Test (DET)—which you can take from your computer. To prevent cheating we time the test and turn on the front-facing camera. We started off with the education market, because you need a certification to get to a US university.

How much does it cost? How many institutions have accepted it so far?
$49. Over 200 now accept our test, many of them very well known such as UCLA, NYU, and Yale.

What's your business model—and endgame?
Our revenue streams are approximately 49 percent from advertising and about the equivalent from people who pay to remove the ads. Two percent of monies are coming from the growing language certification business. Endgame? To become a publicly traded company.

Finally, can you talk about the AI tutors you're creating?
We have conversational AI chatbots, and we keep experimenting on where best to put them in the app. They used to be in their own tab, but we're now putting them inside the main flow so sometimes you'll get a lesson, and other times you'll be asked to have a conversation with one of our AI bots, either via typing, or using the mobile device's built-in microphone.

Do people do better while chatting with an AI tutor?
Yes. We've done many tests and know that using Duolingo app as it was, for 34 hours, gets the same results as a semester in a classroom. But the gold standard is still 1:1 tutoring so we want to develop AI bots for everyone. We've also found that when people talk to an AI, they don't feel judged.

Which is ironic because that's exactly what the AI is designed to do.
Right. But people don't tend to get as embarrassed practicing a new language with an AI as they do with a human. We want to make our AI teachers as good as a human ones—because most of our English language learners can't afford to go to a class. This is their best option to get out of poverty.

Learn Game of Thrones' High Valyrian For Free