Words you already know
Every word in the subtitle is colored by your level: new, learning or known. It also works in Japanese, Mandarin and Thai, which don’t put spaces between words. Your known-word count grows with every episode.
Korean subtitles on the dramas you already watch.
Synced Korean subtitles, word by word, with the sentence and the exact moment saved to your vocabulary. Where the platform doesn’t offer them, we transcribe.
More than 8,000 shows and films indexed word by word.
Supported platforms
- YouTube
- Netflix
- Viki
viki.com/videos/…
생각보다 훨씬 춥네요.
It's much colder than I expected.
훨씬hwol-ssin
much more, by far
An intensifier used only in comparisons. It needs something to compare against — here it’s explicit in 생각보다 (“than I thought”). Without a comparison, use 아주 or 정말.
SaveAsk the AIAnki
- New
- Learning
- Known
See any word in thousands of scenes.
A dictionary tells you what a word is. A scene shows how it’s said.
진짜jinjja
really
59,052times in subtitles
352shows
Subtitles are just the start
Seeing a word doesn’t teach it. What teaches it is what happens after the click.
Vocabulary with the scene attached
Saving a word keeps the whole sentence and the exact second it was said. Months later, one click takes you back to the scene, with the character’s voice and expression.
Ask instead of searching
A dictionary explains a word on its own. It doesn’t explain slang, register, or why an expression means something else. The AI sees the current subtitle and answers about it, with the history saved per conversation.
Straight to Anki
Export your words with the sentence, reading and translation, ready for the deck you already use. No copy-paste, no formatting.
Pricing
Subtitles and vocabulary are free, forever. The paid plan covers what is expensive to run.
Free
$0
No card, no time limit.
- Dual subtitles in the original language
- Vocabulary with the sentence and the second in the video
- Known words, unlimited
- Anki export and import
- Vocabulary synced across devices
- Automatic translations
- 50 quick explanations a day
Pro Founder price
$8$5/mo
For the first 50 subscriptions, kept while the subscription stays active. After that, $8/mo.
- Everything in Free
- 200 quick explanations a day
- Transcription for shows without subtitles
- AI chat
- Natural, high-definition voice
Where the subtitles come from
Two sources that fill in exactly where the other falls short — and we always show which one is in use.
Human transcription
Official subtitles and community archives
When the platform already offers subtitles in the original language, or a file transcribed by native speakers exists, that’s what you get. It’s the most accurate source there is — just synced to the stream automatically, with nothing for you to adjust.
Automatic transcription
What nobody has transcribed
A new season, an episode that aired yesterday, a title that never had original-language subtitles. We transcribe those and add them to the index, starting with what our users tried to watch.
It joins a queue and is ready within 1 hour.
For Japanese, the community archive comes from Jimaku and Kitsunekko, kept up by volunteers for years. Our subtitles stay open and credited, and we give back to the archive what we transcribe.
The subtitles sit on top of your video app.
On your phone you don’t switch players. Open the video app you already use and the subtitle bar appears over the picture — full screen, in sync with the dialogue.
생각보다 훨씬 춥네요.
It's much colder than I expected.
The bar sits on top of the player, full screen. The yellow bubble in the corner is the only part that takes touches.
Your finger stays on the player
The bar doesn’t intercept touches: play, pause and the progress bar still belong to the video app. Only the 48-pixel bubble in the corner takes your touch — less than 1% of the screen.
Tap the bubble and the video stops
The video pauses and the subtitle words become tappable. Tap a word, read what shows up, tap the bubble again and the scene picks up where it left off.
The subtitles keep pace with the scene
The video app publishes its playback clock and the bar follows it. On a real device the measured error was ±5 ms — the eye only notices drift at around 100 ms.
Questions
Why do I need subtitles in the original language?
Because watching with translated subtitles teaches little: your eyes read the translation and skip the original. Many platforms stream in the native language but only subtitle in translations — Crunchyroll is the best-known case.
Are automatic subtitles reliable?
They’re good for clear dialogue and make more mistakes with proper names, overlapping speech and scenes with loud music. That’s why they’re always marked as automatic, and human transcription takes priority when it exists. You know what you’re reading.
Which languages work?
Japanese is where we’re most complete. Korean and Mandarin are in development. Dual subtitles and automatic translation work on any video with subtitles available.
Do I have to subscribe to use it?
No. Subtitles, vocabulary, automatic translations, Anki and sync across devices are free with no limit. The subscription raises the AI limits and adds the AI chat and the natural voice — the parts that cost money per use.
Is my vocabulary saved?
Yes, and you can export all of it at any time, including if you cancel. A word you learned is yours.
Which video apps does it work with on Android?
With apps that publish an Android media session — most streaming players do. The bar shows up on its own when a video is playing and disappears when none is; you don’t have to tell it which app you opened.
Why does Android warn that the app can see what I tap?
It’s the system’s standard text for the permission to draw over other apps, and it can’t be suppressed. StreamFluency uses that permission only to draw the subtitle bar: it doesn’t read the screen and never uses accessibility services.
Does the overlay get in the way of the player controls?
No. The subtitle bar lets every touch go straight through to the video app. The only surface that intercepts touches is the bubble in the corner, and that’s what turns on study mode.
Your next episode could be a lesson.
Install it in your browser or on your phone, open any episode, and watch the subtitles appear.