# lull

> lull is an audio-first, adaptive language-immersion app. You listen to short
> stories generated in your target language at your exact level, tap once on any
> word you don't know, and lull adapts the difficulty and weaves that word back
> as spaced repetition. It is designed to be used eyes-free - with earbuds, on a
> walk, or while driving.

lull is built on comprehensible input: content kept just above your current
level ("i+1"), delivered by ear, with spaced repetition automated so you never
build or grade a deck by hand. It currently supports Brazilian Portuguese and
Indonesian, and is in early access. The model only proposes scripts; trusted
code validates every one against your known vocabulary, so the level is
guaranteed, not hoped for.

## What lull is

- An audio-first language learning app for committed intermediate learners, aimed
  at the "intermediate plateau" between beginner apps and native content.
- The default experience is earbuds plus a blank screen with a single tap target.
- It supports Brazilian Portuguese and Indonesian today; language is a swappable,
  registry-driven dimension, so more can be added.

## How it works

- [Calibrate](https://trylull.xyz/how-it-works): a quick self-rating plus a short
  frequency-banded comprehension probe estimates your starting level. lull does
  not claim a precise word count it cannot back up; the level keeps refining as
  you listen.
- [Listen](https://trylull.xyz/how-it-works): lull generates a short story from the
  words you know, a few new ones, and any words due for review.
- [Stay at the right level](https://trylull.xyz/how-it-works): a trusted validator
  checks every generated script against your closed vocabulary and repairs any
  out-of-set words before playback. The model proposes; trusted code decides.
- [Tap](https://trylull.xyz/how-it-works): while listening, the whole screen is one
  tap target. Tap when you hear a word you don't know.
- [Adapt and review](https://trylull.xyz/how-it-works): lull resolves the tap to the
  intended word, schedules it with a spaced-repetition engine (FSRS), and weaves
  due words back into future stories and quick flashcards.

## Key features

- [Stories generated at your level](https://trylull.xyz/how-it-works): freshly
  generated and validated against the words you know.
- [One-tap, eyes-free marking](https://trylull.xyz/how-it-works): mark unknown words
  without looking at the screen.
- [Automated spaced repetition](https://trylull.xyz/how-it-works): FSRS scheduling
  with review woven into listening.
- [Genre and topic steering](https://trylull.xyz/how-it-works): the topic changes;
  the vocabulary ceiling does not.
- [Learn from your own content](https://trylull.xyz/how-it-works): point lull at a
  YouTube video or paste lyrics or a transcript, and it builds a lesson around the
  words that are new to you.
- [Cross-language head start](https://trylull.xyz/how-it-works): a Spanish speaker
  learning Brazilian Portuguese starts higher because lull pre-seeds the shared
  and cognate vocabulary.

## FAQ

- [What is lull?](https://trylull.xyz/faq): an audio-first language-immersion app.
  You listen to short stories at your level, tap words you don't know, and it
  adapts difficulty and schedules those words for spaced review.
- [Which languages does lull support?](https://trylull.xyz/faq): Brazilian
  Portuguese and Indonesian today, with a registry built to add more.
- [Can I use it while driving?](https://trylull.xyz/faq): yes - it is audio-first
  and screen-optional. Earbuds in, eyes closed, a single tap to mark a word.
- [How does it keep stories at my level?](https://trylull.xyz/faq): a trusted
  validator checks every generated script against your known words and repairs any
  out-of-set word before you hear it. Comprehensibility is guaranteed by code.
- [Is it free?](https://trylull.xyz/faq): it is free to try during early access;
  iPhone pricing is still being finalized.

## Links

- [Open the lull web app](https://app.trylull.xyz): try lull in your browser.
- [How it works](https://trylull.xyz/how-it-works): the full walkthrough of the loop.
- [FAQ](https://trylull.xyz/faq): answers about lull.
- [Home](https://trylull.xyz): the lull landing page.