How I Learned 3 Languages in 7 Months -- for Free

duolingo free foreign language program
duolingo.comDuolingo creators Luis von Ahn, left, and Severin Hacker

Last year we introduced you to Duolingo, the new(ish) online business that hopes to teach foreign languages to everyone in the world -- you included -- for free.

Since then, the Internet language learning site (available on PC and Mac, as well as on Android, iOS and Windows mobile devices) has attracted some 85 million users around the world, according to Head of Communications Gina Gotthilf. That's a big number, considering that according to S&P Capital IQ, Duolingo has only been in business since 2011. But the service's popularity isn't surprising.

In independent, third-party studies, 34 hours of online Duolingo study has been shown to deliver language proficiency equal to one semester of college-level language instruction -- which could cost upwards of $900 at published tuition rates .

Anecdotally, many users agree that completion of an entire language "tree" (course of study) on Duolingo delivers proficiency roughly equal to two full years of college study, but takes only months to complete. Gotthilf says completion of a tree is designed to bring a student to level "B1" on the Common European Framework of Reference for Languages scale -- which, according to Framework guidelines, provides "intermediate" fluency where a student can, for example, "deal with most situations likely to arise while traveling in an area where the language is spoken."

Today, Americans can gain similar fluency, and replace such expensive college study, in any of 10 different foreign languages currently offered by Duolingo, while speakers of 21 different foreign languages can learn English.

A Bit of History

Founded by Carnegie Mellon professor Luis von Ahn, the same man who invented the "reCAPTCHA" system that Internet sites use to confirm whether you're a human or a robot, Duolingo is a company on multiple missions. For one, by harnessing the "wisdom of the crowd," Duolingo wants to translate large portions of Wikipedia into other languages, disseminating that knowledge around the globe. Simultaneously, Duolingo aims to make English language learning accessible to folks who don't have a lot of money to spend on expensive language learning software packages.

In furtherance of both these missions, Duolingo is teaching people around the world to talk to each other.

It's noble work, to be sure. But how does Duolingo pay the bills?

The Economics of Online Education

Originally funded by venture capital, Duolingo set out to fund its ongoing operations itself, by selling translations (prepared by students in the course of practicing their skills) to companies such as CNN and BuzzFeed, which would pay to have content translated. Over the past few months, however, Duolingo has veered away from that course, seeking new ways to self-fund that wouldn't distract from its core missions.

Recent months have seen the company, for example, expand sales of branded merchandise from its online store. Duolingo's also exploring the idea of charging a small fee for language instruction for corporate and government clients. Most intriguingly, though, is one project that Duolingo has begun that promises to both make its services more useful to users and at the same time generate a modicum of revenue to fund its business.

Duolingo calls the new service "Test Center." In a nutshell, it's an online, remotely proctored test to certify a foreign student's English language proficiency (a prerequisite for enrolling at a U.S. college). To date, Gotthilf says about a dozen leading U.S. universities are considering accepting Test Center certification in lieu of the widely used Test of English as a Foreign Language exam to prove English language fluency.

Internationally, Princeton, New Jersey-based ETS charges foreign students as much as $250 to take the Toefl. Test-prep courses for the Toefl can add $2,000 or more to this tab. Duolingo, in contrast, charges just $20 for the test itself -- and provides all the test-prep a student wants, for free.

In this way, Duolingo is able to generate revenue while at the same time enhancing the practical value of its language courses to students. The company is in the process of setting up certification testing for U.S. students studying foreign languages as well, to help students "prove" language fluency and thus strengthen their resumes.

Does It Work?

Now, there's a natural suspicion that, when being charged $0 for a service, students might "get what they pay for." In Duolingo's case, however, that's not the case. You get a whole lot more than you (don't) pay for.

Taking on the role of guinea pig, I began using Duolingo to study Spanish back in August. Three months later, I'd finished the Spanish learning "tree," and then moved on to study German, and then Portuguese. Those last two took about two months each to complete.

And yes, Duolingo does work. While not conversationally fluent, I can attest that after completing any given learning tree, I was able to translate Wikipedia articles, offered as translation exercises by Duolingo, from Spanish, Portuguese or German, into English, pretty easily. And in line with anecdotal evidence, I agree that completion of any given tree is about equivalent to language proficiency gained through four semesters of college study.

And the fact that it took me just seven months, or barely the length of one semester to learn three languages on Duolingo, at zero cost? That's just guinda del pastel -- icing on the cake.

Motley Fool contributor Rich Smith currently speaks more than six languages -- English, Russian, Arabic, Spanish, Portuguese and German. Some of them, he even speaks well. He has no financial interest in any company named above.