Fluidity family · Chrome

Support

Chrome 120+ on desktop. Homepage: submersion.usefluidity.com

Install

1. Open chrome://extensions and turn on Developer mode.
2. Load unpacked, and pick the folder that contains manifest.json.
3. Pin Submersion. In the popup, set Study and Gloss, then play a title that has those captions.

Study and Gloss can each be Japanese, English, Korean, Chinese (Simplified), Chinese (Traditional), Spanish, French, German, Portuguese, Italian, Russian, Arabic, Hindi, Thai, Vietnamese, Turkish, Polish, Dutch, Swedish, Indonesian, Ukrainian, Czech, Romanian, Hungarian, Greek, Hebrew, Finnish, Danish, Norwegian, Malay, or Filipino. Click-for-meaning uses Semantide for Japanese, Chinese, French, and English, and a translation for every other language in that list.

After you change the folder, reload the extension and hard-refresh the player. Overlay scripts do not update from save alone.

No overlay, or only one language

• Turn captions on in Netflix or YouTube at least once for that title.
• Match Study / Gloss in the popup to tracks the title actually has.
• If there is no gloss track, turn on Invent a translation when a track is missing in the popup.
• Submersion cannot add languages Netflix or YouTube did not give your account.

Keys

• Z last line
• X this line again
• V upcoming line
• P pause each line
• U unblur
• B keep this line
• − / = speed
• Space play / stop (still belongs to Netflix or YouTube)

Any webpage

Open an article in your study language, click the Submersion button, and choose Submerge this page (or right-click → Submerge this page, or Alt+Shift+S). Click a word for the same card you get on captions; a faint dotted line marks words you have not met, Studying words get an aqua wash, and Solid words recede.

Links keep working: a plain click follows the link, and holding Shift over a word looks it up. Text you select stays selectable. The Words button lists the page’s vocabulary with how much of it you know. To have a site switch on by itself, turn on Always on in the popup; Chrome asks for that one site.

Not on Chrome’s own pages, the Web Store, Netflix and YouTube (they use the player overlay), or editors such as Google Docs. Text inside frames, canvases, and closed web components is out of reach. Turning it off removes everything Submersion added; the page itself is never rewritten.

Your personal reading library

Save multiple texts, organize collections, search documents, resume reading and listen with sentence-by-sentence text-to-speech.

Reader

Review saved vocabulary inside Submersion

Guests can use local spaced repetition without an account. Signed-in review is permission-gated and is not currently activated in production.

Review

Learn languages through videos

Explore Netflix and YouTube captions, local video files, and supported HTML5 players with interactive Study and Gloss tracks.

Watch

Kept words and privacy

When signed in, kept words enroll in Fluidity and shared decks synchronize automatically. Source context and kept lines stay local. Offline caches reconnect later. See the Privacy Policy.

Chrome Web Store listing

When a store listing is live, this page remains the support URL. Until then, install is unpacked from the folder that contains manifest.json.