Duolingo

Duolingo is a free language-learning program. Its website and mobile apps can be used on iOS, Android, Windows 8 and 10 operating systems. Duolingo allows people to learn over 106 different language courses in 43 languages.

History
The project was started by Professor Luis von Ahn and graduate student Severin Hacker. The main development language used was Python.

 Products and services 
 Courses 
 Language courses 
Duolingo has 185 language courses teaching 43 languages.

CEFR based language courses for learners of Chinese (Mandarin), English, French, German, Italian, Japanese, Korean, Portuguese, and Spanish are available for all users. Additional courses are also available for speakers of English (Arabic,  Czech, Danish, Dutch, Esperanto, Finnish, Greek, Haitian Creole, Hawaiian, Hebrew, High Valyrian, Hindi, Hungarian, Indonesian, Irish, Klingon, Latin, Navajo, Norwegian, Polish, Romanian, Russian, Scottish Gaelic, Swahili, Swedish, Turkish, Ukrainian, Vietnamese, Welsh, Yiddish, Zulu), Chinese (Chinese (Cantonese)), Arabic (Swedish), and Spanish (Catalan, Guarani, Russian, Swedish).

Offices and workforce
Duolingo is headquartered in Pittsburgh, Pennsylvania, and has offices in Seattle, New York, Detroit, Beijing, and Berlin. Duolingo employs around 830 people.

 References 

Other websites

Category:American websites
Category:Learning