In honor of World Tattoo Day, Duolingo, the world’s #1 language learning app, offered the world a unique new social service: to check and correct their foreign language tattoos. For two weeks starting on March 21st, we invited anyone with a foreign language tattoo to post a photo of their ink to social media with the #TattooDuoOver (or to email us if they were feeling shy), and then invited the worst, most horrible, borderline unforgivable translation mistakes to Paris to receive a cover-up with the phrase they really wanted.

Millions of people have tattoos in languages they don’t understand. And, unfortunately, many of these tattoos don’t actually say what they’re supposed to. Ariana Grande, for example, set the internet on fire when it turned out her Japanese tattoo didn’t say “7 Rings” as she’d intended, but actually said, “Barbeque Grill.” Duolingo’s approach to language learning has always been based on one guiding principle: learning a language should be fun. And there’s nothing fun at all about a language mistake that you can’t take back. So we set ourselves a goal, what if we could turn the most embarrassing language mistake into a language lesson the whole world could benefit from?

Our idea was simple: to use social media to check the world’s foreign language tattoos for grammar and spelling mistakes, and then offer the worst errors a free cover up with the word or phrase they really wanted, plus a free subscription to Duolingo’s premium service, Duolingo Plus, to be sure they learned from their mistakes.

Knowing that millennials, who make up the heart of Duolingo’s target audience, are the most tattooed generation on the planet, and that foreign language tattoo fails like Ariana Grande’s have already torn through social media, we knew that an idea based around tattoos would speak to our audience. We kept our focus on the most relevant social media channels for this audience (Facebook, Twitter, Instagram) and launched on World Tattoo Day to amplify our impact in the press. After all, who better to solve the world’s most embarrassing foreign language mistake, than the world’s #1 language learning app?

We launched with a film on social media featuring a wily tattoo artist who comically prayed on naive tourists. The film invited people to submit photos of their foreign language tattoos using #TattooDuoOver for a free translation check. From there, we worked with a team of Duolingo language experts to check submissions and respond to each with the good or bad news. At the end of the two weeks, we picked the 3 worst mistakes and invited them to Abraxas Tattoo Parlor in Paris to have their tattoos fixed.

The campaign generated more than half a billion media impressions, with over 6 million organic views on the launch video. We received over a thousand submissions on Facebook, Instagram, Twitter, and e-mail, and saw a follower increase of 167% across social channels. The campaign also generated one of the most engaged posts in the brand’s history across all channels. But most importantly, we can rest easy knowing that now three unlucky language lovers aren’t walking around with tattoos that say, “I love poo,” “I hate pretty girls,” and “Born too lose” in languages they don’t know.