What Is a Language Learning App That Uses YouTube and Netflix Videos?

A language learning app that uses YouTube and Netflix videos turns the shows and clips you already watch into study material. Instead of building vocabulary from a fixed course list, you watch real content with dual subtitles, click any word for an instant translation, and save it to a personal wordlist that a spaced repetition system reviews later. Lokia is one example: it's a browser extension for Chrome, Firefox, and Edge that works on YouTube and Netflix, plus an app for iPhone, iPad, and Android. It's worth considering if you already spend time on those platforms and want that time to double as vocabulary practice — and less useful if you need structured grammar lessons or speaking practice.

How dual subtitles and clickable words turn videos into lessons

The core mechanic is simple: you watch a video you'd watch anyway, but with two subtitle tracks running at once — the original language and a translation. From there:

• Dual subtitles show the original language and the translation together, both on the video and in the transcript panel.
• Interactive subtitles let you click any word or phrase to get an instant translation.
• Save to wordlist adds that word directly to a personal collection for later review.
• Progress tracking shows your knowledge level for each word inside the extension.

The practical effect is that you never leave the video to look something up. You encounter a word in a real sentence, in a real voice, at real speed — then capture it in one click. That context is the main thing a course-based app can't replicate, because course dialogues are written to teach, not to sound like actual media.

What "context-rich" actually means here

Lokia's feature list describes context-rich learning as seeing words in multiple contexts with example sentences, so you can understand usage patterns and nuances rather than just a one-to-one translation. In practice, this means a saved word isn't a single flashcard with one meaning — it accumulates the different sentences where you met it.

How FSRS spaced repetition schedules your review

Saved words don't just sit in a list. Lokia reviews them with flashcards using FSRS (Free Spaced Repetition Scheduler), an algorithm that sets review intervals based on how well you know each item, aiming for long-term retention.

If you've used older spaced repetition systems, the difference is in how intervals are calculated. Rather than fixed rules like "review in 1 day, then 3, then 7," FSRS models your recall probability and schedules the next review at the point where you're about to forget. In the app, each card gives you grading options — the interface shows Again, Hard, Good, Easy — and your choice feeds back into the schedule.

Two things follow from this:

• You review less than you'd expect for words you consistently rate Easy, because intervals stretch out.
• The quality of your grading matters. Rating everything "Good" out of habit flattens the signal the algorithm uses.

What custom wordlists and progress tracking add

Beyond the default flow, you can create personalized vocabulary collections — searching, translating, and organizing words that matter to you. Progress tracking then shows statistics and a per-word knowledge indicator, so you can see which words are solid and which keep coming back.

This is the part that makes the app usable for different goals. If you're watching a series in your target language, you can build a wordlist around that show's recurring vocabulary. If you're preparing for a specific topic — cooking, tech, news — you can organize around that instead.

How this differs from traditional flashcard or course-based apps

The trade-off is real. A video-based approach gives you authentic input and vocabulary that sticks because you met it in a story — but it assumes you can already parse some of what you're hearing. If you're starting from zero, a structured course will get you to the point where real content is usable faster. Many learners do both: course for grammar, video app for vocabulary and listening.

Which platforms and languages are supported

• Browsers: Chrome, Firefox, and Edge, via a free extension that works on YouTube and Netflix.
• Mobile: available on the App Store for iPhone and iPad, with install options for iOS and Android.
• Languages: the site states support for over 50 languages, with a language list that loads on the page.
• Interface: works on desktop and mobile, with light and dark mode.

The extension is described as free. The site has a pricing page, so if cost matters for your situation, check that page directly rather than assuming everything is free — the free label applies specifically to the extension in the site's own wording.

When to try it, and when to look elsewhere

Try it if: you already watch YouTube or Netflix in your target language, you want vocabulary to come from content you actually enjoy, and you like the idea of a review queue that builds itself from what you watch.

Look elsewhere if: you need grammar instruction, speaking practice with feedback, or a fully guided beginner path — none of which a subtitle-and-flashcard tool is designed to provide.

A reasonable first test: install the extension, watch one video in your target language with dual subtitles on, save five words, and see whether the review flow fits how you like to study. That single session will tell you more than any feature list.