Hello folks. I hope you are gonna have a fantastic weekend ahead, as I am bringing you a big update for Captionz! I’m launching Captionz‑ext, an ultra-lightweight browser extension that finally makes dual subtitles on YouTube practical. Thanks to auto‑translate, you can pair almost any language, do quick A‑B repeats, and add community notes, all while you watch.

As you know, dual subtitles have always been my goal. Finally they’re realistic for most videos, which means our second subtitle can finally show up 🙂
And the best part: Captionz is completely free. I first thought I’d need AI to translate captions (which would cost money), but YouTube already provides auto‑translate. I just enhance the experience and bring both subtitles together.

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Why This Is a Milestone

My goal is to help you learn from real videos, like movies, interviews, lectures, and news etc. without losing your flow. I built Captionz‑ext to make dual subtitles practical on most YouTube videos by adding auto‑translate when only one track exists. It also syncs with the Captionz web app for tools like A‑B repeat, notes, and search. Simple setup, more learning.

Free — No Fees

Early on, I planned to use AI to translate captions, which would have meant a paid “pro” plan. Thankfully, YouTube already has auto‑translate. Captionz‑ext simply connects the dots so you can see two subtitles at once. Enjoy Captionz completely free.

What’s New Auto‑translate: Turn it on to cover almost any language. If a video has only one caption track, auto‑translate adds the second. Dual subtitles: My core goal, now practical on most videos. See two languages at once. One‑click access: I added a “Watch on Captionz” button on YouTube video pages. Context menu: I added a right‑click menu to open any YouTube link in Captionz. Sync with Captionz: Captions flow into Captionz, so A‑B repeat, notes, and Dictionariez work right away.

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How It Works

I built Captionz‑ext to read the captions (and auto‑translated ones) on YouTube, then sync them with the Captionz web app. Many videos only include one auto‑generated track, auto‑translate provides the second. Pick your two languages and watch them side by side. No complicated setup, no secret switches.

A Brief History

Five years ago, I launched the first version of Captionz. My debut post on Reddit was a hit: “I made a site that helps you watch YouTube with dual subtitles”.

Back then, I didn’t need an extension. YouTube captions were public; you could request and download tracks, and Captionz could combine languages freely.

Later, YouTube restricted external caption requests. To keep things working, I added a handy button in Dictionariez so users could still open videos on Captionz with dual subtitles — at least for videos that had multiple tracks by default.

A few months ago, YouTube encrypted caption requests, which made access harder. I switched to a simple, privacy‑friendly approach with a lightweight extension and separated Captionz from Dictionariez. That keeps Dictionariez focused and gives Captionz users a stronger, dedicated tool.

And yes: I made Captionz‑ext free and open‑source. High‑fives all around.

Who It’s For Learners: Compare native + target language subtitles in real time to build comprehension and confidence. Teachers & Tutors: Use any YouTube video for bilingual instruction with A‑B looping and notes. Polyglots: Switch language pairs and auto‑translate to explore content across the world. Casual Viewers: Understand more, faster—without pausing to look things up. Quick Start Chrome: Install from the Chrome Web Store. Edge: Install from Microsoft Edge Add‑ons. Firefox: Firefox Add‑ons.

Open any YouTube video and click “Watch on Captionz.” Or right‑click a video link and choose “Open in Captionz.” Pick your two languages, turn on auto‑translate if needed, and you’re set. Your coffee can stay hot; setup is quick.

Manual Installation (Alternative) Download the source code from GitHub. Go to chrome://extensions/ in your browser. Enable Developer mode (top right). Click Load unpacked and select the extension folder. Privacy

I aim for minimal, respectful integration. Captionz‑ext only accesses captions needed to enable features and does not collect personal browsing history. Read the privacy policy for details and updates.

FAQs Do dual subtitles work on all videos? It depends on captions. Many videos have only one auto‑generated track; turn on auto‑translate to add the second language. Which languages are supported? Auto‑translate covers most languages YouTube supports. Dual subtitles work when two tracks exist or one is auto‑translated. Do I need the Captionz web app? The extension helps on YouTube and pairs with Captionz for A‑B repeat, notes, and more. Together is best. Does this work on Shorts? Not at the moment. Do you really want it to work on Shorts? Comment below to let me know. Is it free? Yes — and there are no AI translation fees. Auto‑translate is provided by YouTube; Captionz just enhances the experience. Call to Action

Install Captionz‑ext (it’s free) and try dual subtitles on your next video:

Chrome: Captionz – YouTube Dual Subtitles Edge: Captionz – YouTube Dual Subtitles Firefox: Captionz – YouTube Dual Subtitles.

Open a video you love, turn on auto‑translate to widen language coverage, and use A‑B repeat to nail tricky lines. Add a note or two to help the next learner (or future you).

TL;DR

Captionz + Captionz‑ext = dual subtitles on YouTube—made practical by auto‑translate—plus A‑B repeat and notes, across almost all languages. It’s completely free. Click “Watch on Captionz” and start learning faster. Smiles optional, progress guaranteed.

Hey! Hope you had an awesome weekend.

Just wanted to share an update I’m really excited about: I’ve been working on Captionz, and it just got a major upgrade! 🎉 It now supports language-specific search, which means you can search for words spoken in a particular language inside YouTube videos.

So, for example—if you’re learning Swedish like I am—you can type in any Swedish word (or English word?), and Captionz will show you YouTube videos where people are actually speaking Swedish. No more digging through irrelevant content. It’s like turning YouTube into your own personal language-learning search engine.

Ever tried using YouTube to learn a language?

Maybe you're following some cool SFI teachers or native speakers on YouTube—maybe it’s French, Spanish, Japanese, whatever. That’s awesome, but YouTube doesn’t really give you good tools to learn from those videos, right? That's where Captionz comes in. It’s made specifically for language learners who want to use real, native content to study smarter.

Here’s what it can do:

Dual subtitles? Yep. See both the original language and your native language side-by-side. Super helpful for understanding context and structure.

A-B repeat? You got it. Replay a sentence or phrase over and over until it sticks. (Yes, it’s that good ol’ A-to-B loop feature from back in the day!)

Search any word or phrase? Big yes. Want to hear how native speakers say “hej då” or “ça va”? Search it and boom—real people saying it in real videos.

Add notes? Kind of. Right now, you can add notes during the video, and they’ll fly across the screen like flying bullets. It’s a fun start, but still in development—private notes and better note management are on the roadmap.

Why this matters

This project really means a lot to me. I love YouTube, and I genuinely believe it’s one of the best tools for language learning. There’s always someone out there creating exactly what you need to hear or see—you just need a better way to find it. That’s the whole idea behind Captionz.

Whether you're just starting out or you're already deep into your language journey, I hope Captionz makes it easier, more interactive, and honestly, more fun.

A few quick tips to get the most out of Captionz

Use dual subtitles to compare sentence structure and learn natural phrasing.

Loop tricky sentences with A-B repeat and shadow them until they sound natural.

Search new words you encounter in lessons and see how they’re actually used by native speakers.

Follow channels in your target language and combine them with Captionz for a powerful study combo.

Thanks for reading this far! 😄 I’d love for you to try it out and let me know what you think. More features are in the works, and your feedback helps shape where this goes next.

By the way—what language are you learning right now? And do you have a favorite YouTube channel for it? Comment under the topic. I’m always looking for good recommendations!

Happy learning!

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