Credits and licences
Penko Vox: Japanese is built on excellent open-source software, AI models and data. These components keep their own licences, and your rights under those licences are not limited by our terms.
| Component | Licence |
|---|---|
| Qwen3.5Language model behind the AI tutor · Qwen team, Alibaba Cloud | Apache License 2.0 |
| llama.cppRuns the language model on your computer · ggml.org | MIT License |
| kotoba-whisperJapanese speech recognition model · Kotoba Technologies | Apache License 2.0 |
| whisper.cppSpeech recognition engine · ggml.org | MIT License |
| ReazonSpeechJapanese speech recognition model · Reazon Human Interaction Lab | Apache License 2.0 |
| sherpa-onnxSpeech recognition and synthesis runtime · k2-fsa | Apache License 2.0 |
| Silero VADDetects when you start and stop speaking · Silero Team | MIT License |
| KokoroJapanese voices (speech synthesis) · hexgrad | Apache License 2.0 |
| kuromoji.jsSplits Japanese sentences into words · Takuya Asano | Apache License 2.0 |
| JMdictJapanese dictionary data · Electronic Dictionary Research and Development Group (EDRDG) | Creative Commons Attribution-ShareAlike 4.0 |
| WanaKanaConverts between romaji and kana · WaniKani | MIT License |
| ts-fsrsSchedules Study Hub reviews (FSRS) · Open Spaced Repetition | MIT License |
| three.js3D graphics · three.js authors | MIT License |
| ReactUser interface · Meta Platforms, Inc. and affiliates | MIT License |
| ElectronDesktop app framework · OpenJS Foundation and Electron contributors | MIT License |
| ChromiumWeb engine included with Electron · The Chromium Authors | BSD 3-Clause License and others |
| steamworks.jsSteam integration (achievements, cloud saves) · ceifa | MIT License |
Dictionary data
Penko Vox: Japanese uses the JMdict dictionary files. These files are the property of the Electronic Dictionary Research and Development Group (EDRDG), and are used in conformance with the Group's licence (Creative Commons Attribution-ShareAlike 4.0): https://www.edrdg.org/edrdg/licence.html
Chromium includes many open-source components; their licences are listed in the LICENSES.chromium.html file in the app's installation folder.
The full licence texts are included with the app. Questions: contact@penkosoftware.org.