Duosub — Dual Subtitles for YouTube

Learn a language on YouTube with two subtitles at once — the original and yours. Click any word to look it up. Private, free.

Turn every YouTube video into a language lesson. Duosub shows two subtitle lines at the same time — the original language you're learning on top, and your own language below — perfectly synced over the player. When a word trips you up, just click it to look it up. No pausing to open a dictionary, no switching tabs, no losing your place. ★ TWO SUBTITLES, IN SYNC See the original and the translation together. Choose which line sits on top and the size that reads best for you. ★ CLICK ANY WORD Tap a word for an instant look-up. Chinese and Japanese are split per character, so even single glyphs are clickable. ★ HOVER TO PAUSE Move your cursor onto a subtitle line and the video waits while you read. Move away and it plays on. ★ 38 CAPTION LANGUAGES Spanish, French, German, Japanese, Korean, Arabic, Hindi, Portuguese, Chinese and many more — powered by YouTube's own caption translation, so it's completely free to use. ★ SPEAKS YOUR LANGUAGE The whole extension — popup, settings, on-video labels — is available in 13 interface languages. ★ PRIVATE BY DESIGN No account. No analytics. No servers. Duosub reads the captions YouTube already provides and does everything in your browser. It asks for a single permission — storage — to remember your language settings. Perfect for learners at any level, from following along with your favorite creators to studying a scene line by line. Not affiliated with YouTube or Google.