SRS Spaced Repetition
Wrong words auto-enter the SM-2 spaced repetition queue, pushed precisely by algorithm — LangKey's core differentiator from immersive translators.
SRS Spaced Repetition
SRS (Spaced Repetition System) is LangKey's core differentiator. Wrong words don't just flash by — they get scheduled for review precisely via the SM-2 algorithm.
What is SM-2
SM-2 is a decades-old spaced repetition algorithm used by Anki and others:
- Correct → lengthen next review interval (1d → 3d → 7d → 30d ...)
- Wrong → shorten interval (re-learn in 1d)
- 4-grade rating: didn't know / wrong / hesitated right / fluent — affects interval growth
Where Wrong Words Come From
All practice modes auto-capture unfamiliar / wrong words:
| Mode | Trigger |
|---|---|
| Input Mode | Misspelled, missing, or extra word |
| Option Mode | Picked wrong option |
| Fill-in Mode | Answer doesn't match original |
| Listening Mode | Misheard / wrong pick |
| Shadowing | Pronunciation not scored, wrong words enter vocab |
| Dictation Mode | Any wrong word |
| Selection Translate | Actively saved words |
When a wrong word enters VocabularyDB, it automatically records:
- Original sentence context
- Source URL (video / article)
- Source platform (YouTube / Bilibili / TED / any web page)
- CEFR level estimate
Review Panel
Open LangKey popup → SRS Review:
- Due today: words SM-2 says need review today
- Overdue: longer-overdue words get higher priority (avoid permanent forgetting)
- New words: max 20 new words join the queue daily
- 4 rating buttons: Again / Hard / Good / Easy
Cross-Device Sync
Pro with cloud sync enabled, SRS progress syncs in real time across all Chrome / Edge / Firefox — study on mobile, review on desktop.
Anki vs LangKey SRS
| Feature | LangKey SRS | Anki |
|---|---|---|
| Source of wrong words | Auto-captured, no manual entry | Manual card creation |
| Context | Auto-records original sentence / URL / platform | Must add manually |
| Review entry | Browser popup | Standalone app |
| CEFR estimate | ✅ | ❌ (extra plugin needed) |
| Algorithm | SM-2 | SM-2 (default) |
Feedback
Report SRS rhythm or scoring issues on GitHub Issues.