Subz intelligently highlights uncommon vocabulary in real-time captions, delivers instant definitions with native audio pronunciation, and builds your personal vocabulary notebook—without ever breaking your flow.
Click any highlighted word in the subtitles below to preview pronunciation, meaning, and context in real time.
"We need to dissect the subtle nuances of this sentence."
Subtle highlights, instant definitions, and zero distraction. Everything you need to master English naturally while watching what you love.
Filtered against 10,000+ essential words so only meaningful, high-yield vocabulary is highlighted. Everyday conversation and common terms stay untouched.
Pre-loaded seamlessly in background memory so cards appear instantly the moment you click. Zero loading spinners, zero waiting.
Dual-speed pronunciation (1.0x and 0.75x) lets you train your ear to catch natural native phonetics and word stresses in conversational English.
Integrated directly with YouTube. Resume playback or rewind 5 seconds with a single click to hear the word again in its original scene.
Save any word with its in-scene context quote. Build a lasting daily habit with our 5-word goal progress bar and streak tracker in the popup dashboard.
Take your vocabulary anywhere. Export your complete study sheet with definitions, parts of speech, and dialogue context to a clean text file for Anki, Notion, or offline study.
Add Subz to Chrome in one click. Open any YouTube podcast, interview, or tutorial with English captions.
Subz subtly underlines unfamiliar words right inside your subtitles without interrupting your movie or lecture.
Click any word to reveal its simple definition, listen to native audio, bookmark it, and hit Resume!
Your saved words, learning streaks, and preferences never leave your browser. Subz has no external tracking scripts, requires no account login, and never collects your browsing history. Everything is stored locally on your device.
