By Carmen Sesin

Luis von Ahn, the co-founder of the popular language-learning platform Duolingo as well as the cyber-security system CAPTCHA and reCAPTCHA, is the recipient of the 2018 Lemelson-MIT prize, which awards a mid-career inventor whose patented product or process has significantly improved society.

The $500,000 prize, the largest cash prize for invention in the U.S., was formally announced on Wednesday at the MIT Technology Review's EmTech conference.

He is currently working full-time as the CEO of Duolingo, a free technology platform, including Apps, offering 82 language courses to over 300 million users around the world, to make language learning accessible.

He is also the cofounder of CAPTCHA, which stands for Completely Automated Public Turing, widely used by websites to tell computers and humans apart. It requires users to retype a few computer-generated characters to prove they're not a robot.

Websites use it to authenticate registration to a website, protect email addresses and block scalpers from buying and selling tickets. He also invented reCaptcha, which digitizes books and archives.

In an e-mailed statement to NBC News, von Ahn, who is a Carnegie Mellon University consulting professor, said his mission is to use technology, like he did with Duolingo, to level the playing field when it comes to knowledge and education.

“It’s been my life’s dream to be able to invent new technology that can help reduce inequality by making high-quality education accessible to everyone," said von Ahn to NBC News. “From my upbringing in Guatemala I’ve seen that education is the key to opportunity and equality, but I’ve always felt it’s unfair that the best education is often only available to those with money.”

Von Ahn came to the U.S. from Guatemala in 1997 to study at Duke University, where he graduated summa cum laude. He went on to earn his doctorate in computer science at Carnegie Mellon University in Pittsburgh where he now lives.

Growing up in Guatemala, von Ahn saw many injustices that impacted him for life. “I saw the difference between those who had access to education – not just education, but a lot of things — and those who didn’t,” von Ahn told NBC News a year ago in an interview at Duolingo’s Pittsburgh headquarters.

“Guatemala is a very poor country. I went to a very fancy high school where everybody kind of had a lot of resources, but very nearby or nearby where I lived, there were people and friends I had who were not able to eat dinner that night,” he said.

About 15 percent of language classrooms in the U.S. use Duolingo and the number is growing. It's also used in public schools in various countries, allowing schoolchildren and people to learn another language for free. It uses techniques from games and casinos to get learners to stick with it, von Ahn said.

“Luis has created a novel resource for the people around the world who need to learn a new language,” said Stephanie Couch, executive director of the Lemelson-MIT Program in a statement. “For some users, Duolingo is key to survival in a new country. Others use Duolingo to learn a language for business, leisure or travel. Luis’ dedication to harnessing the power and promise of technology to engage and empower learners of all types is truly inspiring.”