Why it works

Why the words finally stick.

FluentOtto is built around four simple ideas about how people really pick up a language. Here’s what each one looks like in a lesson.

Otto at a desk with a notebook and a lamp, one paw raised as if he just understood something

See it and hear it, and it sticks.

Every sentence is read aloud while each word lights up. Your eyes and ears work together, so you understand more and remember more.

ResearchLearners who hear words while reading them understand more and learn more new words.See the study ↗

In your lesson

Esta noche, el equipo local juega la final.

The word being spoken is highlighted as you go.

Never lose the thread.

Your own language sits right under every sentence, so you always know what you just heard, and you keep going instead of getting stuck.

In your lesson

El estadio está lleno desde las seis.

The stadium has been full since six.

Unknown word? Tap it.

Hear it on its own, see what it means, and it’s saved for later. No dictionary, no stopping.

ResearchExplaining a word the moment you meet it helps you learn it.See the study ↗

In your lesson
juegaplays · from jugar, to play

Saved to your word list.

Learn from what you love.

Every lesson starts with a topic you picked, so you actually want to find out what happens next.

ResearchPeople learn more new words from topics they find interesting, and remember them longer.See the study ↗

In your lesson
Game DayTrue CrimeHistory

Your topic, your level.

The difference

Not another drill app.

Drills and flashcards

  • Words on their own, out of context
  • The same exercises for everyone
  • Translate in your head, then guess
  • Easy to put down and forget

A FluentOtto lesson

  • Words inside a real topic you care about
  • Written for your exact level
  • Your language right beside every sentence
  • You want to know what happens next
See how it works
Relevant research
  • Montero Perez, M., Van den Noortgate, W., & Desmet, P. (2013). Captioned video for L2 listening and vocabulary learning: A meta-analysis. System, 41(3), 720–739.See the study ↗
  • Brown, R., Waring, R., & Donkaewbua, S. (2008). Incidental vocabulary acquisition from reading, reading-while-listening, and listening to stories. Reading in a Foreign Language, 20(2), 136–163.See the study ↗
  • Wang, A., & Pellicer-Sánchez, A. (2022). Incidental vocabulary learning from bilingual subtitled viewing: An eye-tracking study. Language Learning, 72(3).See the study ↗
  • Yanagisawa, A., Webb, S., & Uchihara, T. (2020). How do different forms of glossing contribute to L2 vocabulary learning from reading? Studies in Second Language Acquisition.See the study ↗
  • Lee, S., & Pulido, D. (2017). The impact of topic interest, L2 proficiency, and gender on EFL incidental vocabulary acquisition through reading. Language Teaching Research, 21(1), 118–135.See the study ↗
  • Patall, E. A., Cooper, H., & Robinson, J. C. (2008). The effects of choice on intrinsic motivation and related outcomes: A meta-analysis of research findings. Psychological Bulletin, 134(2), 270–300.See the study ↗

See it work on your own topic.

Why it works · FluentOtto