Trancy

Trancy is a browser extension and mobile app designed for language learners who consume a lot of video and web content. It automatically overlays bilingual subtitles on YouTube, Netflix, TED, Udemy, Disney+, and other platforms, and lets you customize fonts, colors, and layouts (including a 'theater' or 'reading' mode). It also offers inline word translation, paragraph translation, and full-text translation when browsing regular websites.

Learners can save new words to a built-in flashcard collection, practice pronunciation through sentence repetition, and use AI to generate video summaries. These features create a lightweight learning loop from input to output. The free tier covers essential translation and subtitle functions, while a premium subscription — reported at $29.99/year in some sources — unlocks additional tools like PDF translation and advanced speaking exercises.

A notable drawback is that on mobile, the best experience requires using Safari with the Trancy extension rather than native apps like YouTube; the Safari experience still has minor quirks compared to a dedicated app.