story no. 01
YingYu.io
A pronunciation coach for kids, scored on-device.
Role
Creator & Solo Developer
Timeline
2026 — now
Company
YingYu.io
Stack
Flutter · ONNX · Dart
Part 01
Kid-friendly Flutter App
A landscape Flutter app for Android tablets and macOS, with illustrated scenes, a mascot-led sign-in and large touch targets sized for young learners.
Part 02
Lesson Home
The current lesson and its progress up front, with one-tap entry to written homework, word and passage review, and daily word and passage check-ins.
Part 03
Graded Homework
Homework comes back as one page: the brief, what the learner handed in, and the teacher's grade with a score badge, a written comment, a voice review to play and annotated photos of the work.
Part 04
Word Practice with On-device TTS
Word cards with IPA, the Chinese meaning and natural audio generated on the device by the Kokoro TTS model (ONNX). Learners record their own attempt and play it back against the model voice. This screen is still being built.
Part 05
Phoneme-level Pronunciation Scoring
A quantized Wav2Vec2 CTC phoneme model decodes each recording on-device. The result is aligned against the target US/UK IPA to score every sound and give an overall 0–100 grade. The check-in review lists each word with its per-phoneme scores, attempts and the recording, so weak sounds stand out.
Part 06
Coming Next: Listening and Reading
Two study modes are on the way: 磨耳朵 (ear training), daily listening to build an ear for English sounds, and guided reading of short passages. Both slots are already in the app, marked as coming soon.
6
features
12
technologies
8
months on it
