Duetbook
日本語 Coming soon

Hear any book in two languages.

Duetbook writes out what the narrator says, line by line, with a translation under each line. The word being read lights up as you listen.

Coming soon to the App Store

For iPhone. Free to download, and Pro is a one-time purchase.

The first lines of Don Quijote

Read in Spanish, with English under each line. Press play, or tap a word to hear it from there.

En un lugar de la Mancha, de cuyo nombre no quiero acordarme, no ha mucho tiempo que vivía un hidalgo de los de lanza en astillero, adarga antigua, rocín flaco y galgo corredor.In a village in La Mancha, whose name I’d rather not recall, there lived not long ago a gentleman of the old sort: a lance on the rack, an ancient shield, a skinny horse and a fast greyhound.

Una olla de algo más vaca que carnero, salpicón las más noches, duelos y quebrantos los sábados, lentejas los viernes, y algún palomino de añadidura los domingos, consumían las tres partes de su hacienda.A stew with more beef than mutton, leftovers most nights, eggs and bacon on Saturdays, lentils on Fridays and a young pigeon as a treat on Sundays took three quarters of his income.

Recording from LibriVox, read by Lu (public domain). The transcript and the timing of each word were made by Duetbook, with a few misheard words corrected.

Every sentence, then its translation, aloudPro

Put your phone away and keep learning. Duetbook plays the book one sentence at a time and reads each one again in your language, in a voice of its own.

  1. En un lugar de la Mancha, de cuyo nombre no quiero acordarme…

    The narrator reads a sentence

  2. In a village in La Mancha, whose name I’d rather not recall…

    A voice reads it in your language

  3. A pause the length of the sentence.

    If you like, a pause to say it yourself

Hear the translation before or after the original, or on its own. Leave a pause to repeat each sentence aloud if you like, hear it several times, slower the first time, and choose how fast the translation is read.

Study what you hear

Tap a word you don’t know, keep the sentences you want to remember, and check what you can catch by ear.

Tap a wordSee its dictionary form, its reading and what it means, hear it, or save it for review.
Review with the narrator’s voiceSaved sentences and words come back in the Review tab with their audio, on a spaced-repetition schedule.
DictationWrite what you hear. Duetbook marks the words you missed or misspelled, and keeps the sentence for review.
Take the transcript with youExport it as text, as SRT, VTT or LRC subtitles, or as a CSV for flashcards in Anki.
Ask whyGet a sentence explained in your language: what it says and the words in it, and its grammar with the downloaded AI model. All made on your iPhone.

Your books never reach us

Transcripts and translations are made on your iPhone. There is no Duetbook server to send them to.

  • No account, no ads, no tracking

    Open the app and add a book. Nothing about you or your listening is collected.

  • Made on the device

    Speech recognition and translation built into iOS do the work, and they keep working offline once a language is downloaded.

  • Add-ons, downloaded once

    Whisper, for languages iOS can’t transcribe such as Arabic and Russian. A natural Japanese voice. An AI model that translates the next few minutes again, reading the sentences around each one.

  • Synced through your own iCloud

    Your library, where you are in each book and what you saved follow you to your other devices. Apple keeps them in your account, where we can’t read them.

An audiobook player first

Everything you expect from a good audiobook app is here, for the books you own.

  • Your audio files

    MP3, M4A, M4B and other files without DRM, from Files, a folder or a zip.

  • A folder becomes one book

    Tracks play in order as one book, with a chapter for each file.

  • Any speed

    From 0.5× to 4×, at the narrator’s own pitch.

  • Sleep timer

    Stop after a set time or at the end of the chapter.

  • Bookmarks and chapters

    Mark a place with a note and jump between chapters.

  • Podcasts

    Follow shows and get transcripts and translations for their episodes too.

  • EPUB and PDF, read aloud

    Books made of text become audiobooks, with the karaoke transcript.

  • CarPlay

    Your library and controls on the car’s screen.

  • Apple Watch

    Play, pause and skip from your wrist.

  • Widgets and the Lock Screen

    Pick up where you left off without opening the app.

  • Siri and Shortcuts

    Ask Siri to resume your book, add a bookmark or save the sentence you just heard.

  • iCloud sync

    Your library and your place in each book, on every iPhone you use.

Whatever language your book speaks

HolaHelloBonjourこんにちはHallo안녕하세요Ciao你好OláПриветمرحبا

Transcribed on your iPhoneEnglish, Spanish, French, German, Italian, Portuguese, Japanese, Chinese and Korean with the speech recognition in iOS. The free Whisper download adds languages such as Arabic and Russian.

Translated into yoursWith Apple’s translation, on the device, into any language it offers. Duetbook itself is in English, Japanese, Spanish, French, German, Italian, Portuguese, Korean and Chinese.

Free to start. Buy Pro once.

There is no subscription. Pro stays unlocked for good, for your family too.

Duetbook

Free

  • The whole audiobook and podcast player
  • Karaoke transcripts that follow the narrator
  • A translation under every line
  • Tap a word for its meaning
  • Up to 20 saved sentences and words in Review
  • The first chapter of an EPUB or PDF read aloud

Duetbook Pro

$24.99once

  • Translations read aloud, sentence by sentence
  • Unlimited review
  • Dictation
  • Explanations of a sentence’s words and grammar
  • The AI translation model
  • Whole EPUB and PDF books read aloud

Try Pro free for 14 days. Shared with your family through Family Sharing.

Questions

Can I add books I bought in other audiobook apps?

Only if you have them as audio files without copy protection (DRM). Duetbook plays MP3, M4A, M4B and other DRM-free files, podcasts, and EPUB and PDF books it reads aloud. Free recordings of classics from LibriVox work well, like the one above: here is one to start with in each language.

Does it need an internet connection?

Transcribing, translating and reading aloud happen on your iPhone. You need the internet once to download a language or an add-on, and to find and download podcasts.

Which iPhones can run it?

Any iPhone with iOS 26. Explanations use Apple Intelligence on iPhones that support it, or the downloadable AI model. Duetbook 1.0 runs on iPad in the iPhone layout; an iPad layout will come in an update.

How good are the transcripts?

As good as the speech recognition in iOS, which is very good for clear narration. Names and old words are sometimes misheard; fix a word once and Duetbook fixes it throughout the book, with the timing kept.

What happens when the free trial ends?

Nothing is lost. Pro features pause until you buy Pro, and everything in the free app keeps working. You are never charged automatically.

Where do my files go?

Into your iCloud Drive, in the Duetbook folder, when you use iCloud; otherwise they stay on your iPhone. The privacy policy lists everything Duetbook keeps and every time it goes online.

I made Duetbook because I learn languages by listening to audiobooks, and I wanted to see every line in two languages while the narrator reads it.

Junichiro Horikawa, the person who makes Duetbook. Questions and ideas are welcome on the support page.