How To Use Language Reactor

Getting Started (2 minutes)

Go to languagereactor.com and install the Chrome extension (it's a browser plugin, not a standalone app).
Once installed, open Netflix or YouTube in Chrome.
Pick a show or video in the language you're learning - Spanish, French, Japanese, whatever you're studying.
Click the Language Reactor icon in your browser. The video player transforms: you'll see dual subtitles (your native language + the target language) at the same time.
Play the video. Subtitles appear line by line. Click any word to see its definition and save it to your vocabulary list.
Use the keyboard shortcuts to pause after each subtitle, repeat the last line, or slow down playback.

Pick based on your level.

Beginner (A1-A2): Watch kids' shows or simple YouTube channels in your target language. Use dual subtitles and pause after every sentence. Repeat it out loud.
Intermediate (B1-B2): Watch a show you've already seen in English - now watch it in Spanish (or your target language) with Spanish subtitles only. You know the plot, so you can focus on the language.
Advanced (C1-C2): Turn off your native language subtitle. Use only the target language subtitle and click words you don't know. Build a vocab list as you watch.
Listening practice: Hide the subtitles entirely (Language Reactor lets you toggle them). Watch a scene, then reveal the subtitles to check what you missed.

Save words to your list. Click any word in the subtitle to add it to your vocabulary deck. Later, export the list to Anki or Quizlet for spaced repetition practice.
Use the slow-down feature without shame. Native speakers talk fast. Dropping to 0.75x speed makes it easier to catch every word without feeling lost.
Watch the same episode twice. First time: dual subtitles, pause often. Second time: target language only, no pausing. You'll be shocked how much more you understand.

Learning grammar from scratch. Language Reactor is for immersion, not grammar lessons. Pair it with Duolingo or a textbook to learn the rules first.
Languages without subtitle support. It only works if the show has subtitles in both your native language and your target language. Some obscure language pairs won't have dual options.