DualSub for All

Dual subtitles on YouTube, hover-to-translate on any page or PDF, vocabulary notebook, flashcards, AI grammar notes.

Learn a language from the content you already watch and read. ▸ DUAL SUBTITLES ON YOUTUBE See the original subtitle and its translation at the same time. Choose any subtitle track and any target language. Hover a word to see its meaning; the video pauses while you look. ▸ HOVER TO TRANSLATE, ANYWHERE Turn on Reading Mode and hold Alt while hovering a word on any website to see its meaning and part of speech. Select a phrase or paragraph to translate it in place. ▸ PDF READER Open PDF files in DualSub's built-in reader and look up words the same way. Works with online PDFs and local files. ▸ ONE-CLICK VOCABULARY NOTEBOOK Click a word to save it with its meaning, the exact sentence you found it in, a translation of that sentence, and a link back to the video or page. Words are grouped by language and by day, so you can review "today's Spanish words" in seconds. ▸ FLASHCARDS AND ANKI EXPORT Review with built-in flashcards (keyboard shortcuts included) or export to CSV for Anki. ▸ AI GRAMMAR NOTES Get an explanation of the grammar around each saved word, word forms, common collocations, and three fresh example sentences with translations. Included with Pro, or use your own Gemini, OpenAI, or Claude API key on the free plan. ▸ YOUR LANGUAGE, YOUR INTERFACE Meanings, saved words and AI notes follow the language you choose. The interface is available in English and Vietnamese. FREE vs PRO Free: dual subtitles, hover-to-translate on web and PDF, PDF reader, flashcards, CSV export, up to 100 saved words. Pro (optional subscription): unlimited words, sentence and paragraph translation, example sentences translated when you save, AI grammar notes with no setup. 14-day money-back guarantee. Private by design: your notebook stays on your device. No ads, no tracking. See the privacy policy for details.