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Watch YouTube with dual subtitles

Show two subtitle lines inside the YouTube player on your desktop computer: the spoken-language caption on top and your translation below it.

Add LangBox to ChromeLangBox runs in Chrome on a computer.Email me the link

Free Chrome extension. Works on YouTube videos with captions, including auto-generated ones.

The desktop Chrome extension runs directly inside the YouTube watch page so it can display dual subtitles over the player and pause after each caption line for dictation or shadowing.

What dual subtitles require

  • Requires the LangBox extension in Chrome on a desktop computer on youtube.com watch pages.
  • The video must already have human or auto-generated captions; live streams and uncaptioned videos are not supported.
  • Translation uses your 2M-token guest trial, your 10M-token 30-day signed-in allowance, or your own API key.

What you get on YouTube

  • Dual subtitles on the video

    The original line with your language under it, in time with the video. Turn it on and off with the LangBox button in the player.

  • Transcript beside the video

    Click Dictation next to Like. The transcript opens on the right, one sentence per line with its translation, and follows the video. Click a sentence to jump to it.

    The bilingual transcript beside a YouTube video

    Real screenshots of the extension on a NASA video. NASA does not endorse LangBox.

  • Dictation practice

    Press D. Each sentence turns into blanks, the video pauses at the end of the sentence, and LangBox checks what you typed word by word.

    Dictation on a YouTube video: typed words are checked word by word

    Real screenshots of the extension on a NASA video. NASA does not endorse LangBox.

  • Shadowing

    Press S in the same panel. Say each sentence after the video, and LangBox shows which words it heard.

    How shadowing works →

How to turn on dual subtitles

  1. Install the extension and open a video

    Add LangBox to desktop Chrome and open a YouTube video that has human or auto-generated captions.

  2. Enable translation in the player

    Click the LangBox button at the bottom right of the YouTube player to translate the caption track.

  3. Read along or open the side transcript

    Follow both subtitle lines during playback, or click Dictation next to Like to view the scrolling bilingual transcript.

Questions

Is it free?
The extension is free. The transcript and dictation need no account. Translation uses LangBox translation: guests get a one-time trial of 2,000,000 tokens, and you can sign in with Google for a monthly allowance or use your own API key.
Can I use it on a phone or tablet?
No. Chrome extensions work only in Chrome on a computer. On a phone, copy or email yourself the link and install it later on your computer.
Which languages are supported?
Any language the video has subtitles in. LangBox uses the subtitles for the language spoken in the video and translates them into the language you choose.

Keep learning after this tool

These tools handle one file at a time. The free LangBox Chrome extension brings the same translation to everything you read and watch, and saves new words for review.

Install FreeLangBox runs in Chrome on a computer.Email me the link