Which language learning platform launched in 2011 with the tagline "Learn a language for free. Forever." and introduced a gamified approach that revolutionized the industry?

In the world of language learning and linguistics, brands constantly innovate to capture market attention. One revolutionary product launch changed how people approach language learning globally, creating a new category of tech-enabled language acquisition. This product's innovative approach to gamification and accessibility disrupted traditional language learning methods and quickly gained millions of users. Can you identify this linguistic breakthrough from its launch details?

This is a live public trivia poll on AIPolls.Net. Vote and see real-time results.

Duolingo
Rosetta Stone
Babbel
Memrise