Polylingual Development
Polylingual Development LLC
Language software built the way languages are actually acquired.
We make Poly Tutor — a bilingual AI tutor for English and Chinese. It reads, chats and watches with you, giving just enough help to understand everything, and less help every week as it learns what you know.
Read
Books at your level
Graded readers from first sentences to full stories. Help appears over the words you don't know yet — everything else is just reading.
Chat
A tutor who talks at your speed
Speak or type in either language. Your tutor answers in Chinese you can understand, with your language right below.
Words
It remembers every word you know
As words become yours, the training wheels come off — everywhere in the app, on their own.
Why it works
Linguist Stephen Krashen showed that we acquire languages through comprehensible input — content just slightly above your level that you can still understand. Because Poly Tutor remembers exactly which words you know, it keeps everything you read and hear in that zone, and simplifies the language — never the substance — of the things you already enjoy.