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Aprende con lo que ya ves.Learn from what you already watch.

DuoSubs shows two subtitle lines on Netflix: the language you are learning and your own. Click any word to translate and save it. Passive Polyglot turns those words into flashcards that come back right before you would forget them.

Get early accessSee how it works
  • Free plan, no card needed
  • Chrome on desktop
  • Works on Netflix today
Example: a Netflix scene with the Spanish subtitle “¿Y si nos quedamos un rato más?” and the English line “What if we stay a little longer?” below it. The word “rato” is clicked, a popup translates it as “a while” and saves it, and a flashcard for “un rato” appears.

Three steps, no study sessions to plan

You keep watching what you were going to watch anyway. The learning happens in the gaps.

  1. 1

    Watch

    Play a show on Netflix with DuoSubs on. The line in the language you are learning sits on top, your own language below, both in sync.

  2. 2

    Click

    Click a word, or drag across a phrase, to see what it means. Save it with one more click. Selecting text on any other website works the same way.

  3. 3

    Review

    Saved words become flashcards in Passive Polyglot. Spaced repetition brings each one back when it is due, so a few minutes a day is enough.

Every episode feeds your deck

Words you save on Netflix land in Passive Polyglot on their own. No copying, no typing. Here is the path a single word takes.

  1. Episode 3, 12:04

    You click “rato” and save it.

  2. Same evening

    First review. Miss it and it comes back in ten minutes.

  3. Tomorrow

    It returns once. Get it right and the gap grows.

  4. Days, then weeks

    Each correct answer pushes the next review further out.

  5. 21+ days

    It holds for three weeks and counts as learned.

Built for the couch, then the commute

One half lives in your browser while you watch. The other half is where the words stick.

While you watch

  • Two subtitle lines on Netflix

    The original line and your language at once. Hide either one when you want a challenge.

  • Click to translate words and phrases

    A small popup shows the meaning right over the scene. Shift+click or drag to grab a whole phrase.

  • Any website, too

    Select a word or sentence on a news site, a blog or a recipe, translate it, and save it to the same deck.

While you review

  • Spaced repetition

    Rate each card Again, Hard, Good or Easy. The scheduler decides when you see it next.

  • Listen mode

    Cards are read aloud one after another, for the walk to work or the washing up.

  • Stats, streaks and a heatmap

    See how many cards you reviewed each day and how long your streak is.

  • CSV import and export

    Bring words from another app, or take yours with you. Your list is never locked in.

Passive Polyglot Pro

Translations that know what is happening on screen

  • AI subtitle translation that reads the scene, so idioms and jokes come out right
  • AI example sentences and emoji hints on your cards
  • Unlimited saved words (Free keeps up to 100)

Coming soon

  • Prime Video
  • Disney+
  • Max
  • YouTube
  • Mobile app

Free to start, Pro when you want more

The free plan is the full loop: subtitles, translation, saving and flashcards. Pro adds AI and lifts the word limit.

Billing period

Free

Everything you need to start learning from Netflix.

$0

No card needed

  • Two subtitle lines on Netflix
  • Click any word to translate it
  • Translate text on any website
  • Save up to 100 words
  • Flashcards with spaced repetition
  • CSV import and export
Get early access

Pro

AI that understands the scene, and no limit on words.

$49per year

$4.08 a month, billed once a year

  • Everything in Free
  • Unlimited saved words
  • AI subtitle translation that understands the scene
  • AI example sentences and emoji hints on cards
  • Sync across devices

Prices in US dollars. Questions about billing? Write to rk@coldabry.com.

Questions, answered

Something missing? Write to rk@coldabry.com.

Which streaming services does it work with?

Netflix, today. Prime Video, Disney+, Max and YouTube are planned, and we will say so here when each one works.

Which browsers are supported?

DuoSubs is a Chrome extension for desktop. Other browsers are not supported yet.

Which languages can I learn?

Any language a show has subtitles in. You choose the language you are learning and your own language, and the two lines follow those choices.

Do I need my own Netflix account?

Yes. DuoSubs adds subtitles and translation on top of the Netflix you already pay for. It does not give access to any content.

What happens when I reach 100 saved words on the free plan?

Your cards stay and you can keep reviewing all of them. To save new words, upgrade to Pro or delete cards you have learned.

What does Pro add?

AI subtitle translation that takes the scene into account, so idioms and jokes make sense. AI example sentences and hints on your cards. And no limit on saved words.

Is there a mobile app?

Not yet. Passive Polyglot is a web app, so your flashcards open in your phone's browser. A mobile app is planned.

Can I cancel Pro?

Yes, any time from your account page. Pro stays active until the end of the period you paid for, and your cards stay with you.

What does the extension read?

The subtitles of what you play and the text you choose to translate. Words you save go to your account so they can become flashcards. See the privacy policy for details.

Tu próximo episodio es tu próxima clase.Your next episode is your next lesson.

Get early access

Free to start. Pro is optional and you can cancel any time.