Leitner helps you build lasting English vocabulary using the proven "Leitner Box" spaced-repetition method. Instead of rote memorization, words you're learning resurface right when you're about to forget them — deeper retention with less effort.

Features:

• 🗂️ 5-stage Leitner box system — each correct answer moves a word forward; a wrong answer sends it back to the start.
  
• 📅 Daily review — only shows the words actually due today, not everything at once.
  
• ➕ Add new words with automatic dictionary lookup (tap "more meanings" for extra translations)
  
• 📖 Two-way dictionary (English↔Persian) with live autocomplete
  
• 📚 Leveled English stories with Persian translation — tap any word for its meaning and add it straight to your word bank
  
• 🎬 Educational videos filterable by genre and level
  
• 🔊 Text-to-speech pronunciation
  
• 🏆 Mastered words archive for vocabulary you've fully learned
  
• 🌓 Custom color themes and an optional bidirectional review mode
  
• 💾 Backup & restore to move your word list to a new phone
  

No sign-up or account needed — everything is stored locally on your device.