Dual Subtitles for YouTube — prost

Sync two subtitle tracks on YouTube (e.g. original + translation).

Watch YouTube with two synced subtitle tracks — original and translation. Choose languages, style the overlay, learn faster.

Dual Subtitles for YouTube shows two synchronized subtitle tracks on the same video — for example the original language and a translation — so you can read both at once without switching tracks in the player.

What you can do
Pick two languages from the caption tracks available for the current video (primary and secondary).
Stay in sync: both lines follow playback together.
Choose how you read: Dual (original + translation), Original only, or Translation only.
Customize the overlay: font size, colors for primary and secondary text, and background opacity — readable on any video.
Turn the extension on or off from the popup when you need a clean player.
Who it’s for
Language learners, anyone comparing wording across languages, and viewers who want bilingual captions on YouTube without juggling settings on every video.

How it works
The extension runs on YouTube watch pages, uses the same subtitle data YouTube offers for that video, and displays your chosen tracks in an overlay. Preferences are saved locally in your browser; we do not collect accounts or personal data, and there is no separate analytics server in this version. See the privacy policy linked from the listing for details.

Note
Subtitles must be available on the video. If a language or track is missing, it cannot be invented — the lists reflect what YouTube provides for that clip.