Anki
Open Source
Anki is a spaced repetition flashcard program. Anki is the Japanese word for memorization.
AnkiApp
Commercial
AnkiApp is a flashcard app for iOS (iPhone + iPad), MacOS, and Android.
Lingvist
Free
Lingvist is an adaptive language-learning platform.
Babbel
Commercial
Babbel is a subscription-based language learning app and e-learning platform.
Memrise
Freemium
Memrise is a Language learning Platform with a website and iOS and Android Apps.
Busuu
Freemium
Busuu is a social network for learning languages.
VocApp.com
Free
VocApp.com is a vocabulary improvement software platform.
Compare Duolingo with alternatives
Compare VocApp.com and Duolingo and decide which is most suitable for you.