SubLingo - Dual Subtitles & Language Learning

About

SubLingo is the language learning extension built for people who learn by watching.

It adds dual subtitles to Netflix, YouTube, TED, and Coursera — your target language on top, your native language below — so every episode becomes a language lesson. No separate app. No switching tabs. Just watch, and learn.

━━━ LANGUAGE LEARNING THROUGH CONTENT ━━━

The most effective way to acquire a language is through comprehensible input: content you almost understand. SubLingo makes every video on Netflix, YouTube, TED, and Coursera a language learning opportunity by keeping the translation one glance away at all times.

Dual subtitles let you read in your target language first, then confirm understanding with your native language below. Over time, you glance at the translation less. That's acquisition.

━━━ DUAL SUBTITLES ━━━

See both subtitles simultaneously, perfectly synced to the audio. Choose which languages to display, or show only one. Switch languages instantly from the in-video controls without pausing.

Supported on Netflix, YouTube, TED, and Coursera. Works with 48+ languages including Spanish, French, Japanese, Korean, Chinese (Simplified & Traditional), German, Portuguese, Italian, Vietnamese, Arabic, and more.

━━━ HOVER TRANSLATE ━━━

Hover over any word in the subtitle to get an instant translation with part of speech and sentence context. It works while the video plays — no need to pause, copy, or switch to Google Translate. The fastest way to fill in vocabulary gaps in the middle of a scene.

━━━ VOCABULARY BUILDER ━━━

One click saves a word directly from the subtitle, together with the full sentence it came from. Your vocabulary list grows passively as you watch, in the side panel next to the video. Every saved word is timestamped to the show and episode you were watching.

━━━ SMART FLASHCARDS WITH SPACED REPETITION ━━━

Every saved word automatically becomes a flashcard. SubLingo uses FSRS — the same spaced repetition algorithm used by Anki and Duolingo — to calculate the optimal review time for each word based on your personal memory curve.

7 exercise types adapt to your language learning level:
- Translation recognition (beginner-friendly multiple choice)
- Listening recognition (train your ear)
- Context cloze (fill in the blank from a real subtitle)
- Fill in the blank (type the word from memory)
- Translation production (type the meaning)
- Reverse production (type the word in your target language)
- Image recognition (associate words with visuals)

Words move through 5 mastery stages: new → learning → young → mature → mastered. The algorithm prioritizes words you're about to forget, so every review session counts.

━━━ TRANSCRIPT PANEL ━━━

Open a full scrollable transcript of the episode. Click any line to jump to that moment in the video. The current subtitle is always highlighted. Useful for rewatching a sentence you missed, or for reading ahead in a dense scene.

━━━ CLOUD SYNC — PREMIUM ━━━

Your language learning progress — vocabulary, flashcard history, mastery levels — syncs in real time across all your devices. Start a review session on your laptop and continue on your desktop.

━━━ FOCUS MODE — PREMIUM ━━━

Block distracting websites during your language learning sessions. Set the sites you want to block, and SubLingo enforces them while you study. Stay consistent.

━━━ CUSTOM SUBTITLE STYLES — PREMIUM ━━━

Adjust font size, color, weight, and background for each subtitle line independently. Make the dual subtitles feel native to the platform you're on.

━━━ SUPPORTED PLATFORMS ━━━

• Netflix
• YouTube
• TED
• Coursera

━━━ SUPPORTED LANGUAGES ━━━

Learn from content in: English, Spanish, French, German, Italian, Portuguese, Dutch, Russian, Polish, Turkish, Swedish, Norwegian, Danish, Finnish, Czech, Romanian, Hungarian, Greek, Ukrainian, Arabic, Hebrew, Hindi, Bengali, Urdu, Persian, Swahili, Japanese, Chinese (Simplified), Chinese (Traditional), Korean, Vietnamese, Thai, Indonesian, Malay, Tagalog, and more.

━━━ FREE TO START ━━━

Core language learning features — dual subtitles, hover translate, vocabulary saving — are free with no account required. Sign up to unlock flashcard reviews. Upgrade to Premium for cloud sync, custom styles, and focus mode.

━━━ PRIVACY ━━━

SubLingo only activates on supported streaming platforms. No browsing history is collected or stored. Your vocabulary stays local unless you explicitly enable cloud sync by signing in.

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Learn more: https://sublingo.pro/privacy.html

SUPPORT
Questions or feedback? Visit https://sublingo.pro/