TL/DR: Language Reactor is a free Chrome extension that turns Netflix and YouTube into a language classroom. It’s not the most polished tool out there, but its free plan offers more than enough for most learners, and that alone makes it worth recommending.
Language Reactor (formerly Language Learning with Netflix) is a web application and Chrome extension created by two independent developers, David Wilkinson and Ognjen Apic. It adds a layer of language learning features on top of Netflix and YouTube: dual subtitles, a built-in dictionary, vocabulary tracking, keyboard shortcuts, and more.
I’m an upper intermediate Spanish learner — I can hold a conversation with native speakers, though they occasionally need to be patient with me. I’ve been using Language Reactor for a week to sharpen my listening and fill vocabulary gaps, and it’s proven to be quite useful in that.
The tool has been around since 2019 and was covered by The Verge, The Guardian, and Lifehacker when it launched. It’s come a long way since then, expanding beyond Netflix to YouTube, ebooks, podcasts, and even a chatbot for conversation practice.
If you’ve heard of Migaku, think of Language Reactor as a leaner, free alternative. Migaku is more polished and actively developed by a larger team, but it requires a paid subscription. Language Reactor gives you most of what you actually need at no cost.
Who Is This For?
Language Reactor works best if you:
- Are an intermediate or advanced learner who wants to practice with real content, not textbook exercises
- Prefer YouTube and Netflix for more real-world, engaging content
- Want a free tool that doesn’t gut the core features behind a paywall
- Are already using flashcard apps like Anki and want a way to pull vocabulary directly from content you’re watching (export to Anki is a paid feature though)
It’s not a great fit if you expect a sleek, modern interface, or if you need support for streaming platforms beyond Netflix and YouTube (Amazon Prime, Disney+, and others aren’t supported).
How the Extension Works
Once you install the Chrome extension and open a YouTube video or Netflix show, Language Reactor adds a toolbar with controls below the video. Here’s what you get:
Dual subtitles show the original language and your translation at the same time. You can blur the target language to practice listening first, then hover over any word to reveal it — a simple but effective technique.
Keyboard shortcuts are essential to the workflow. The most useful ones are S to replay the current subtitle, A and D to jump between subtitles, and Q to toggle auto-pause (which stops playback after each line). I watch a lot of travel vlogs, food content, and news in Spanish, and navigating sentence by sentence with the keyboard makes it easy to rewind and replay the bits that go by too fast. Once it clicks, you don’t want to go back to watching without it.
The built-in dictionary pops up when you click on any word. It shows definitions, part of speech, example sentences, and for Pro users, an AI-powered explanation from their Lexa assistant. The free dictionary is solid enough for most purposes.
The vocabulary panel ranks words in the current video by frequency and learning stage, which I find genuinely useful. You can mark words as known, learning, or ignore them — and those tags carry over across everything you watch.
The vocabulary panel was the feature that surprised me most. It ranks every word in the current video by frequency and learning stage, updating in real time according to the video. You can mark words as known, learning, or ignore them, and those tags carry over across everything you watch.
Searching for content on YouTube is one of the more underrated features. From within the search bar, you can type your query in your target language, hit the “search with subtitles” button to search and it only shows videos that have proper subtitles available.
What’s on the Website
The Language Reactor website (languagereactor.com) has grown into more than just a companion for the extension. Under the Media tab, you’ll find:
- A YouTube catalogue with curated channels organized by language and topic, including news and other useful content for learners
- A podcast library with a solid selection of authentic audio content
- Ebooks from the public domain, filterable by vocabulary level and length, with text-to-speech built in
- An option to upload your own text or media files to create custom lessons
There’s also an AI chatbot for conversation practice. I had a short conversation about Latin American food — I’d travelled to Peru, Guatemala, and Argentina a while back and couldn’t remember the names of some dishes. I used the audio input, it picked up my Spanish fine, corrected a couple of things naturally, and kept the conversation going. It won’t replace a real conversation partner, but as a low-pressure way to practice output it works better than I expected.
A Few Things to Keep in Mind
I learned Spanish for a week with Language Reactor, and while it was interesting, a couple of things bothered me:
- The interface looks dated. Compared to more modern tools, it feels like it hasn’t had a design update in years, which makes the learning curve steeper than it needs to be.
- There are occasional bugs. Every time I opened a new YouTube video, I got an error message saying captions weren’t loaded — only for everything to work fine once the video started playing. You also need to manually enable closed captions on YouTube before the extension kicks in, though that’s partly a YouTube limitation.
- No dedicated app, and the extension is desktop-only. The website works on mobile, so you can access ebooks, podcasts, the chatbot, and curated content on your phone — but the full video study experience with dual subtitles and keyboard shortcuts requires a computer.
- I haven’t personally tested the Netflix integration. Based on user reports it works well, but subtitle availability varies by country, so not every show will have the language pair you need.
- Development is slow. The team is two people working in sprints, and they’re not great at communicating updates — the roadmap on their forum hasn’t been updated since 2022. That said, podcasts were added in February 2025 and an AI dictionary in August 2024. The tool is alive, just not moving fast.
Free vs. Pro
For most learners, the free plan covers everything that matters. I’d honestly consider subscribing mostly to support the project and keep it free for others — which the developers are transparent about on their website.
The Bottom Line
Language Reactor isn’t perfect, but it solves the right problem: making it easy and free to learn a language through content you actually want to consume. The outdated UI and limited streaming platform support are real limitations, but they don’t undermine the core value.
If you’re learning Spanish, French, Japanese, Korean, or any of the 30+ supported languages, this is one of the tools I’d recommend installing. Start with YouTube videos on topics you already enjoy, use the keyboard shortcuts religiously, and let the vocabulary panel guide what’s worth focusing on.
It won’t replace structured study or a conversation partner, but as a daily habit for exposure and vocabulary building, it’s hard to beat — especially for free.
Language Reactor supports 30+ languages including English, Spanish, French, German, Japanese, Korean, Chinese, Portuguese, Italian, Dutch, Vietnamese, and Russian.
Have you used Language Reactor? I’d love to hear how you’re using it in the comments.
The post A Free Tool to Learn Languages Through Netflix and YouTube: Language Reactor Review appeared first on The Report by Class Central.
