LingoKeep
Adds clickable dual subtitles and spaced-repetition flashcards to YouTube in 4 languages.
LingoKeep overlays YouTube with dual subtitles, original plus English translation, and a click-any-word dictionary of 540k+ entries that pauses the video on a definition. Words you save become flashcards that replay the original clip and get scheduled by FSRS, the same spaced-repetition algorithm serious Anki users switch to. It covers Spanish, Japanese, French, and German, with Japanese specifically segmented and read-annotated since unspaced text can't be clicked otherwise. The extension needs no account to use fully offline on one device; review is free forever, and Pro ($4.99/month or $39/year) adds unlimited card sync and Anki export.
What holds up
- +540k+ dictionary entries map inflected forms back to their dictionary word automatically
- +Spaced repetition runs on FSRS, the scheduler serious Anki users switch to, free forever
- +Works fully signed out — subtitles, dictionary, word list, and review all work offline
- +Japanese gets real segmentation and readings, not just pasted subtitles with no spaces
Mind the limits
- −Free plan syncs only up to 100 cards across devices — more needs Pro
- −Only 4 languages supported: Spanish, Japanese, French, German
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