Duolingo
Duolingo is a website. It is attributed to Luis von Ahn and Severin Guey.
In detail
Recorded genres are educational game.
Its recorded founders are Luis von Ahn and Severin Guey.
Sources
Each source is named with the standing the house places on it, so the evidence can be weighed rather than taken on trust.
reference work · Reputable secondary · Wikipedia
“Duolingo”, English Wikipedia, consulted as further reading
Consult the sourcereference work · Reputable secondary · Wikidata
Wikidata, structured authority record Q2918660: Duolingo
Consult the source