The company launched the Duolingo Test Center app in July 2014, but has just finished a year-long pilot programme with leading US universities including Yale, Carnegie Mellon and MIT.

The test is a divergence from the free language learning app the company launched in in 2012 which now has 120 million users learning 21 languages.

“First we were just teaching English, now we’re also trying to certify”

“It’s a natural extension,” Duolingo CEO, Luis von Ahn told The PIE News. “First we were just teaching English, now we’re also trying to certify and our goal is to become a global certificate for it.”

The exam can be taken on a mobile device, anywhere in the world for $50 – a fraction of the cost of leading English language exams.

The computer adaptive exam takes about 20 minutes and tests students’ ability to read, listen, speak and write English.

The programme relies on front facing cameras to check students’ identity and human proctors who watch students as they take the exam.

Von Ahn argues that having proctors who are located remotely adds another level of security to the Duolingo exam that others can’t.

“When you look at how much of the cheating happens in standardised tests, a lot of times it’s the testing centres that have been compromised…Here you can’t quite do that because you can’t see the proctor,” he said.

A 2014 study of 200 English language learners showed that Duolingo test scores correlate to TOEFL results and are consistent after multiple sittings.

After a successful pilot period, the company is now working to bring more institutions on board. “If the universities ever start offering us in lieu of any of the other tests most everybody will just want to take our test because it’s cheaper and you can take it from anywhere you want,” said von Ahn.