Sotto
What it is
Sotto is open-source, self-hosted language-learning software with CEFR courses and private practice. Its structured course covers grammar, reading, listening, speaking, and writing, and progression depends on demonstrated mastery. Learners can also practice skills without course gates. A vocabulary and grammar memory graph uses SM-2 spaced repetition to schedule reviews and inform adaptive listening. Learners can build classes from articles, papers, YouTube links, or topics, with material leveled to a CEFR course and citations provided. Sotto supports configured AI and speech providers including OpenAI, Anthropic, Ollama, faster-whisper, Kokoro, and Gemini Live; Claude Code and Codex can work as keyless local agents. A documented offline setup runs language models, speech recognition, and speech generation on the user’s hardware. The application, database, and files run on the operator’s own infrastructure, though content sent to cloud providers is subject to their terms. Access options include a browser-installable PWA, terminal client, desktop launcher, and iPad workbook PDF. It is free to run under AGPL-3.0; users pay configured providers directly.
For and against
For
- Covers five core language-learning skills
- Uses SM-2 spaced repetition
- Supports offline operation on user hardware
- Free to run under AGPL-3.0
Against
- Users pay configured AI and speech providers
- Cloud-submitted content follows provider terms
- Windows setup uses WSL2
The verdict
Sotto combines structured courses, adaptive review, and configurable practice in a self-hosted setup. Its free software license does not cover charges from configured AI and speech providers.
Who it suits
Sotto suits language learners seeking structured CEFR study and private speaking practice before working with other people. It is also suited to users prepared to self-host and configure AI or speech providers.
Plans and prices
Self-hosted
Free to run, modify, and redistribute under AGPL-3.0 · You pay configured providers directly
Read 13 Oct 2026 · github.com
On the record
- Access controls
- Self-hosted setup uses a shared password and local learner profiles, with optional WebAuthn passkeys that an administrator can revoke.github.com · read 13 Oct 2026
- Adaptive practice
- A per-course vocabulary and grammar memory graph uses SM-2 spaced repetition to schedule reviews and seed adaptive listening.github.com · read 12 Oct 2026
- AI and speech providers
- Sotto supports provider-selected AI and speech, including OpenAI and Anthropic API keys, local Claude Code or Codex agents, and local Ollama, faster-whisper, and Kokoro components.github.com · read 12 Oct 2026
- Clients
- Sotto offers a browser-installable web app/PWA, a terminal client, and a desktop launcher for macOS, Windows, and Linux; Windows setup uses WSL2.github.com · read 13 Oct 2026
- Costs
- The software is described as free to run under AGPL-3.0, while users pay their configured AI and speech providers directly.github.com · read 12 Oct 2026
- Course skills
- Its graded classes cover grammar, reading, listening, speaking, and writing, with progression gated by mastery.github.com · read 12 Oct 2026
- Course structure
- Its course covers grammar, reading, listening, speaking, and writing, with progression gated by demonstrated mastery.github.com · read 13 Oct 2026
- Credential security
- The README says provider API keys are encrypted at rest with BYOK_ENCRYPTION_KEY and describes a networkless sidecar for refreshing local CLI credentials.github.com · read 13 Oct 2026
- Data and privacy
- Sotto runs its application, database, and files on the operator's stack; content sent to configured cloud providers is handled under those providers' terms.github.com · read 12 Oct 2026
- Data control
- Users run the application, database, and files on their own stack; content sent to configured cloud providers is subject to those providers’ terms.github.com · read 13 Oct 2026
- Desktop and mobile access
- The maker documents a Tauri desktop launcher for macOS, Windows, and Linux, plus an installable browser PWA for phones, tablets, and laptops.github.com · read 12 Oct 2026
- Integrations
- The maker documents Gemini Live API for real-time spoken translation and an MCP server for connecting Claude Code or Codex workflows.github.com · read 12 Oct 2026
- Intended audience
- The maker describes Sotto as private rehearsal for learners who want to practice before speaking with a teacher, tutor, classmate, or stranger.github.com · read 12 Oct 2026
- iPad workbook
- The web app generates class workbook PDFs for annotation in GoodNotes or another app, and the README says the native iPad app targets iPadOS 18+.github.com · read 13 Oct 2026
- License and cost
- The project is licensed under AGPL-3.0 and says it is free to run, modify, and redistribute under the same terms; users pay their AI and speech providers directly.github.com · read 13 Oct 2026
- Mobile apps
- Yesgithub.com · read 19 Sep 2026
- Mock exams
- Practice exams follow Goethe, DELE, Cambridge English, or generic CEFR formats and provide mock feedback, not official scores.github.com · read 13 Oct 2026
- Offline lessons
- Yesgithub.com · read 19 Sep 2026
