Browsing, watching, listening. Learn Spanish, French and 9 more on any site and in YouTube, Netflix and Prime Video subtitles.
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0.29.11
updated 7 Oct 2026
About Otto: Language Learning
Otto turns the web you already read into language practice.
Open any page, or press play on a show, and Otto weaves words from the language you're learning into text written in the language you already speak. The sentence still reads naturally; you just meet new words where their meaning is obvious from everything around them. You set how many, from a few of the most common words to nearly the whole page, and raise the level as you improve.
Click any woven word and Otto shows you what it means: the translation, the dictionary definition, its pronunciation and more. Save it to review later.
LANGUAGES
Otto works in pairs: the language of the page, and the language you're learning.
English → learn French, Spanish, German, Italian, Portuguese, Chinese, Hindi or Arabic
French → learn English
Spanish → learn English
Italian → learn English
Portuguese → learn English
German → learn English
Japanese → learn English
Korean → learn English
Chinese → learn English
Hindi → learn English
Arabic → learn English
More pairs are on the way.
WHY IT WORKS
Most language learning fails for one reason: it's a separate thing you have to make yourself do. An app to open. A lesson to sit through. Sentences about nothing, written for no one.
Otto isn't a separate thing. It lives inside what you were already going to do today. The article you were going to read anyway. The show you were going to watch tonight. You were going to spend that hour regardless, and now it's teaching you a language.
That changes two things. First, you keep going, because there's nothing to keep up with. Second, you remember more, because every new word arrives inside a sentence you understood, about something you actually cared about. That's how meaning sticks: not from a flashcard, but from the moment you needed the word and it was right there.
THE RIGHT AMOUNT FOR YOU
The 200 most common words in a language carry a huge share of everyday text; the top 2,000 carry most of it. Otto's levels follow that curve, from the top 200 up to Native, so you always learn the most useful words first and the page always stays readable.
WORKS ON SUBTITLES TOO
Otto weaves Netflix subtitles and YouTube captions as you watch, so your evening viewing counts as well.
GETTING STARTED
Install, create a free account, pick your languages, and open a page. That's it. Weave every page automatically or only when you ask, and your progress syncs with the Otto iPhone app. The free plan covers everyday reading; Otto Pro and Otto Max give you more.
Don't study a language. Live inside one.