penguen.io is a free vocabulary app built for language learners. Learn the most essential words that cover the majority of daily conversations using science-backed spaced repetition. Choose from multiple practice modes including flashcards, dictation, listen and choose, fill letters, matches and multiple choice. Generate custom word lists, join a global leaderboard, track your streaks and study offline. Supports dozens of native languages. No ads, no subscriptions, completely free forever.