A Chrome extension and web app that adds dual subtitles, a click-to-translate dictionary and subtitle-by-subtitle playback to Netflix and YouTube, with saved-word highlighting, PhrasePump listening drills and an optional paid Pro mode.
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Language Reactor (formerly called Language Learning with Netflix) is a language learning toolbox that works inside Netflix and YouTube through a Chrome extension, and on its own website for books, web pages, podcasts and chat practice. Its job is to make native material usable for study: you watch or read real content in the language you are learning, and the tool adds the scaffolding around it.
On Netflix, the extension adds dual language subtitles, a popup dictionary, precise video playback controls and other study features to films and series. Beyond working as a dual subtitles extension, it also covers vocabulary review, listening drills, an AI dictionary and a chat partner.
The homepage says Language Reactor is already packed with free features, and Language Reactor Pro is an optional subscription that adds speech recognition and machine translation on Netflix, word saving across every feature, a stronger AI dictionary model and chat memory. Prices start at $5.95 for one month on the Pro page viewed from a US location, with cheaper per-month rates on longer terms.
As captured on September 26, 2026, the Chrome Web Store listing showed a rating of 4.2 out of 5 from 4.4K ratings and 2,000,000 users. That figure is an aggregate satisfaction signal from store users, not a measurement of learning outcomes. The extension is offered by Dioco, and the listing showed version 5.1.8, updated July 1, 2026, at the time of capture.
Language Reactor's features fall into three groups: making a video or text understandable, turning what you watch into vocabulary, and moving from passive input to active practice.
These pieces reinforce each other: a saved word is highlighted when it reappears in another video or article, returns in PhrasePump when due for review, and can leave as an Anki card. This shared vocabulary layer is also where the free plan is most limited, because free accounts can save words only inside PhrasePump.
YouTube has content on almost any topic in all major languages, but it may filter out foreign content by default. Two buttons next to the YouTube search bar help here: the left one translates your search text and the right one finds videos with subtitles. Web pages are imported through the right-click menu, and that feature requires the browser extension.
The Language Reactor team publishes a subtitle-by-subtitle routine for the extension. For beginners it looks like this:
Intermediate learners are expected to understand 50% or more of a line on the first listen, and advanced learners 80% or more, consulting the translation or dictionary only if required. For every level the advice is not to get stuck on a difficult structure, because it will come up again. The guidance also suggests about an hour a day focused on listening. An extension setting can grey out infrequent words, so attention goes to the vocabulary that matters most.
One way to learn languages with Netflix in Language Reactor is to watch a series you already like with both subtitle tracks on and auto-pause enabled. The examples below show where each part of the toolbox fits.
Language Reactor fits learners who already watch Netflix or YouTube on a computer and want to turn that viewing time into study, rather than follow a lesson-based course.
Good fit
Weaker fit
The homepage statement about phones and tablets and the FAQ line about Android are not reconciled on the pages checked, which do not spell out which features work on mobile. Store searches also show a naming overlap: apps that use "Language Reactor" in their titles on the App Store are sold by other individual developers, and the search checked returned no listing from Dioco.
Language Reactor is free to use, and Pro mode is optional. The Pro page viewed from a US location showed three subscription terms and a separate Bitcoin option:
| Option | Price shown (US location) | Billing |
|---|---|---|
| Pro, 1 month | $5.95 | Subscription, renews automatically |
| Pro, 3 months | $13.95 | Subscription, renews automatically |
| Pro, 1 year | $39.95 | Subscription, renews automatically |
| Pro via Bitcoin | Any amount, from $7 per month | No recurring charge |
The same three plans are quoted in local currency depending on the customer's country: for a German location the checkout price feed returned 5.33 EUR for the monthly plan, including tax.
What Pro changes, according to the Pro page:
| Feature | Free | Pro |
|---|---|---|
| Netflix subtitles | Subtitles provided by Netflix | Speech recognition for all audio tracks, plus word-for-word machine translations |
| Saving words and phrases | Only while using PhrasePump | Across all features, highlighted everywhere and exportable to Anki |
| Lexa AI dictionary | Basic AI helper | Enhanced AI model |
| Aria chat | Chat in your study language | Aria remembers conversations; memories can be viewed and edited |
The FAQ summarizes Pro more narrowly, as primarily two additional features: machine translations and saving words and phrases. The two pages describe the plan at different levels of detail. The subscription can be cancelled after paying to stop auto-renewal, and after a free trial the account returns to free mode automatically without a charge. Bitcoin payments are not refundable. In the Pro page, FAQ and help pages checked, no refund terms for regular subscription payments were found.
In a user thread about alternatives on the Language Reactor community forum, learners mentioned Migaku, Trancy and FluentAI, as well as a free setup combining asbplayer, Yomitan and Anki. One user described Migaku as more expensive with a limited list of languages, and the free combination as working well but a lot of hassle to set up.
| Alternative | How its own site describes it | Relevant difference |
|---|---|---|
| asbplayer | A browser-based media player and Chrome extension for learners who study through subtitled media | Both a subtitle control and a flashcard creation tool |
| Migaku | Learning by reading and watching content on YouTube, Netflix, Disney+, Viki, X, Reddit and more | Lists Disney+, which Language Reactor does not support yet |
| Trancy | Bilingual subtitles for YouTube, Netflix, Udemy, Disney+, TED, edX, Kehan and Coursera, plus AI word and sentence translation and immersive translation of web pages | Wider list of video sites |
Trancy's page title includes the phrase "Language Reactor Pro", so the name also appears on a competing product's page.
In a community forum thread started in December 2025, four separate users complained about the product's maintenance: one wrote that bugs reported by many users were not being fixed, another was shocked by the lack of updates, a third found the developers not very proactive, and a fourth, while noting that the team is still working on it, said fixes can take weeks if not months. These are individual user reports, not a measured statistic. The official update history lists changes in 2026, including ASR quality improvements, custom subtitle upload on Netflix and chat memory for Aria.
The privacy policy is titled for the Chrome extension under its former name and covers data sent on installation and whenever the user visits netflix.com. That data includes an anonymous user ID from Chrome, the email address of the Chrome account, the user's Netflix country and language, the extension version, the total number of subtitles watched, and the browser version and operating system. The policy says this information is not shared with third parties and is sent over HTTPS. In the policy text checked, YouTube, the website account, the AI features and payments are not mentioned, and there is no statement on whether user data is used to train AI models.
The store privacy disclosure says Language Reactor handles personally identifiable information and declares that data is not sold to third parties outside approved use cases. The listing also notes that the developer has not identified itself as a trader, and that for consumers in the European Union, consumer rights do not apply to contracts with this developer.
Yes. The core toolbox is free, and on Netflix free users study with the subtitles Netflix provides. Pro is an optional paid upgrade.
From a US location the Pro page showed $5.95 for one month, $13.95 for three months and $39.95 for one year. Other countries see prices in local currency, and a Bitcoin option accepts any amount from $7 per month without a recurring charge.
Not yet. The FAQ lists Disney+, Amazon Prime and Android as unsupported for now; the extension runs on Chrome on Windows and macOS computers.
Machine translations and saving new words stop after the subscription period ends, but everything saved earlier stays viewable and exportable.
No. According to the FAQ, the account goes back to free mode automatically.
