Otto weaves your target language into real articles, exactly as much as your level can carry. This one is live: change the language and level, tap the green words.
Otto is built on a simple observation: you learned your first language by meeting words in sentences you mostly understood, thousands of times, until they stuck. Not from lists.
Language research has said it for decades, most famously in Stephen Krashen's input hypothesis: you acquire a language from material that is just slightly beyond your level, not far beyond it. Otto engineers exactly that. The article stays readable because most of it is in your language; the learning lives in the words that aren't.
Otto swaps the most frequent words first: the 200 most common words carry a huge share of everyday text. As your level rises, rarer words join. Every word you meet arrives inside a sentence you understood, which is how meaning attaches, and every word you save keeps its sentence with it.
Memory research consistently finds that testing yourself beats re-reading. So Otto asks before it tells: tap a word you've met before and it blurs the answer until you've tried to recall it. Games and end-of-article tests are built from your own word bank, and your tutor can test you on exactly what you read.
The free app already has everything the method needs: real articles at your level, tap to translate, 20 saved words a day, games, streaks, tests and your tutor. Pro is for the small group of readers who outgrow that.
If you are meeting more than 20 words a day worth keeping, reading whole books in your target language, or drilling vocabulary daily, Pro takes the ceiling off.
FOR ALMOST EVERYONE
Read real articles every day at your level. Tap any word for translation and definition. Save 20 words a day. Play games built from your words, keep streaks and goals, take tests, link with your tutor.
FOR ADVANCED AND HEAVY READERS
Everything in free, with no daily cap on saved words, the full bookshop for reading whole books at your level, every practice mode without limits, and first access to new features.
You can move to Pro from inside the app the day the free limits actually get in your way. Most people never hit them.
Between lessons is where languages are won and lost. Otto gives your students something worth opening every day, and gives you the controls: what they read, what they're tested on, and what you see.
Send any Otto article as an assignment, with a test built from it: comprehension, gap fill, sentence order, word match, spelling, plus your own written questions.
Build tests from the words your student actually looked up and saved. Cycle mode drills until every word is right; single mode checks a direction of your choice.
Name the book, page and exercises and Otto tracks it. Students answer in the app or tick work off to bring to class, and your book library suggests itself for the next student.
A student can run their app in Spanish and still have you teach them French. You set the level and language their assigned work is read and tested in.
See scores by section, mark written answers, leave comments, and see which words they looked up while working, so you know what was hard before the lesson starts.
A direct thread with each student, plus notifications when work is submitted. No more chasing homework over three different apps.
The portal runs in any browser. There is nothing to install and nothing to configure.
Open the tutor portal in your browser and sign in with your Otto tutor account.
Students link to you from their app. Set each one's language, level and usual lesson day; due dates default to their next lesson.
Pick an article or build a test in a couple of minutes. Results, marking and messages all come back to the same screen.
Running Otto across a class or a whole department? We'll help you set up tutors, groups and lesson schedules, and talk through pricing that makes sense for education.
Otto's readers open the app to spend real time with real articles. Sponsored content lives inside that reading, not around it.
Your story written as an Otto article, read with the same swapped-word mechanic and clearly labelled. Readers spend minutes with it, not milliseconds.
Short video placements between feed items, capped per session so they stay welcome.
Reach learners by the language they are learning and the level they read at, across six languages.
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