India, April 7 -- Luis von Ahn revealed why his billion-dollar company, Duolingo, uses a particular test involving taxi drivers before hiring top executives. He spoke about it during an appearance on "The Burnouts," a podcast hosted by Phoebe Gates and Sophia Kianni.

During the conversation, the CEO said, "At Duolingo taxi drivers determine if candidates get hired." Recalling an incident, he explained, "We were trying to hire a chief financial officer for a year and there was one candidate we all really liked."

Ahn recounted that the candidate had a strong resume and they looked like the right person for the job. However, the company decided not to hire the person after they were "pretty mean" to the cab driver on the way from the airpo...