Another competitor, Berlin-based Babbel, says its revenue of more than $115 million comes from the $85-a-year subscription fee it charges its million-plus subscribers. Venture capitalists have pumped in $108 million, ballooning Duolingo’s valuation to $700 million in 2017, $150 million more than the market capitalization of Rosetta Stone, its 27-year-old publicly traded rival.Īlong with teaching more languages (Rosetta Stone offers 25), Duolingo attracts users because its basic ad-supported version is free, compared with the $120 a year Rosetta Stone charges its 500,000 subscribers. Seven years after its launch, it has nearly 30 million active monthly users, according to its own figures. À la Wikipedia, Duolingo enlists volunteers to help create its more obscure courses.

They include little-spoken tongues like Hawaiian, Navajo and Gaelic and the fictional language High Valyrian from the HBO blockbuster Game of Thrones (1.2 million users are studying it).

Duolingo already offers more languages than its competitors do, 36 at last count.

Duolingo app cost