Duolingo

==2010-2011==
Duolingo launched as a closed beta in 2010, before a private beta launch in November 2011.
==2011–2019==
==2019–present==
On August 21, 2019, Duolingo retooled their wordmark and visual language.
==External links==
Category:Education
Category:Websites
Category:Software
Category:International
Category:Crowdsourcing
Category:Education in the United States
Category:Websites of the United States
Category:Android apps
Category:IOS apps
Category:Pittsburgh
Category:Pennsylvania
Category:United States
Category:2010
Category:2010s