Sottovoce: lessons a blind child can follow

When a teacher in a lesson video says "look at this", a blind child is left out. Audio description fixes that, but it needs a trained describer, so fewer than 5 in 100 educational videos have it (DCMP survey). Sottovoce describes lesson videos for blind and low-vision children. It transcribes the teacher, finds every moment they point at the screen and pauses the lesson there. Gemma 4 on AMD Token Factory writes each line for the child's age (5-8, 8-13 or 14-18), in English or Italian, reading numbers and formulas exactly. Qwen3.8, a different model family, checks every claim against the frames, and only checked or teacher-approved lines are voiced. In two NASA lessons, 24 of 32 lines were longer than the teacher's pause, so the lesson waits instead of dropping them. With a false detail planted in every line, the checker caught 24 of 32 and never flagged a correct line. The models cost under a tenth of a cent per minute of lesson. The child can stop the lesson and ask about the picture by voice. The answer is checked before it is spoken, and if the picture can't answer, Sottovoce says so. Pressing M says where each thing is, panned left or right in stereo. Teachers can also just write to the desk, an Evolus agent on Gemma 4 on AMD. It reads the link, language and age, then starts the lesson through Sottovoce's own MCP connector or asks for what is missing. It answers questions about WCAG and the ADA from a knowledge library. When a lesson is done, it writes easy-read notes for the child and an Evolus AI Tool translates them for the family. The workspace runs two workflows, a sub-agent and the chat widget, and the app drives it through the Evolus API. Built with Google ADK (served over A2A), Google Cloud Text-to-Speech and Cloud Run. Live at sottovoce-ai.web.app.