DuetbookPress kit
Duetbook is an audiobook and podcast player for people learning a language. It writes out what the narrator says, line by line, with a translation under each line, and lights up the word being read.
- Developer
- Junichiro Horikawa, an independent developer in Japan
- Release
- November 2026, App Store
- Platform
- iPhone with iOS 26 (iPads run the iPhone layout)
- Price
- Free. Duetbook Pro is a one-time purchase ($24.99, ¥4,000) with a 14-day free trial and Family Sharing. No subscription.
- Transcribes
- English, Spanish, French, German, Italian, Portuguese, Japanese, Chinese and Korean with the speech recognition in iOS; Arabic, Russian and more with the free Whisper download
- Interface
- English, Japanese, Spanish, French, German, Italian, Portuguese (Brazil), Korean, Chinese (Simplified and Traditional)
- Privacy
- No account. Audio, transcripts and translations stay on the iPhone and in the listener’s iCloud. App Store privacy label: Data Not Collected.
About
Add an audiobook you own, or download a podcast episode, and Duetbook transcribes it on the iPhone with iOS 26’s speech recognition and translates it with Apple’s translation. The transcript scrolls with the narrator. Tap a word for its meaning, save a sentence with its audio for the Review tab, or switch on a learning mode that reads every sentence and then its translation aloud, so a whole book can be followed with the phone in a pocket.
It is also a full audiobook player: folders of MP3s become one book with chapters, and there are playback speed, a sleep timer, bookmarks, widgets, Siri and iCloud sync. Optional downloads add Whisper for languages iOS can’t transcribe, a natural Japanese voice and an AI model that translates again with more context.
Images
The icon and the App Store screenshots. Each opens at full size (screenshots 1320 × 2868, icon 1024 × 1024). The books shown are public-domain LibriVox recordings. Use them freely to write about Duetbook.
Japanese screenshots
Contact
For questions, an interview or a code for Duetbook Pro, write through the contact form; I answer by email.