Duolingo

Duolingo is the world's most widely used language learning platform with 500M+ registered users, built on gamification (streaks, XP, leagues) that drives daily habit formation better than any competitor. The AI-powered Max tier ($167.99/year) adds two flagship features: Video Call with Lily (spontaneous free-flowing AI conversation with an adaptive character, with transcript and feedback after each call) and Roleplay (practice real scenarios like ordering coffee in Paris with dynamically responding AI characters). Max currently supports 8 languages: Spanish, French, German, Italian, Portuguese, Japanese, Korean, and English. In early 2026 Duolingo removed many human contractors and accelerated AI content generation — a controversial but strategically significant move. Free tier is genuinely capable for vocabulary and grammar. Super ($95.99/year) removes ads and unlocks offline mode. Best for: self-directed language learners of all ages who want the highest-engagement daily habit-forming app, especially for the 8 supported Max languages where AI conversation practice is available.