In the 1970s and 80s, linguists studying second-language acquisition formulated what is known as the Input Hypothesis. Central to this hypothesis is the idea that learners make meaningful progress when exposed to comprehensible input, or language which is just beyond their current level of understanding.

SynchroTales is an application for building and delivering comprehensible input across many language pairs in audiovisual form.


  • Read and prepare parallel texts across thousands of language pairs, and access hundreds of built-in translations
  • Tight audio-book integration, with free access to recordings in dozens of languages, fully mapped to the source material
  • Lookup millions of word definitions using the built-in dictionaries, or bring your own
  • Generate in-context spaced repetition flashcards based on your current vocabulary
  • Find and present personally tailored comprehensible input from works in your library
  • Track your learning progress for each language studied
  • Sync documents and media between your devices
  • Works entirely offline!

The rest of the documentation explores this functionality in greater depth.