How to read along with an audiobook you own: sync your EPUB with MP3 or M4B files
You have the ebook and the audiobook as files. Here is how to get the text highlighted as the narrator reads, in about 30 seconds, and learn the language while you do.
You have a book twice: as an ebook and as an audiobook, a folder of MP3s or one M4B. You'd like to see the text light up as the narrator reads it, the way Kindle and Audible do for the books they sell. Here is how to do that with your own files, and how long it takes.
We make Readuet, the app this guide ends with, so read it with that in mind.
The short answer
You need two files of the same book, the ebook and the audiobook, and an app that aligns them: it works out when each sentence is spoken, so the right one can light up.
- Bought both from Amazon? Kindle and Audible already do it for you, in their own apps.
- Have your own files and a home server? Storyteller aligns them on your own hardware.
- Have your own files and want to start now? Upload both to Readuet. About 30 seconds later the opening is ready and you're reading along. The rest of the book lines up while you read.
What you need
An ebook: EPUB, MOBI, AZW3, FB2 or TXT.
The audiobook of the same book: MP3, M4B, M4A, AAC, OGG, OPUS, FLAC or WAV. One file or many: an audiobook in 40 MP3s is fine, they play in filename order.
The same edition. This is the one thing worth checking before you start. Small differences don't matter: front matter, a publisher's blurb, a narrator's introduction, a spoken "Chapter One" the page doesn't have. But the highlight drifts and never catches up when the audiobook is:
- abridged and the ebook is the full text;
- a different translation of the same work;
- a dramatisation with several actors, music and cut lines.
More in our guide to reading along with the narration.
Kindle and Audible: only for books bought from Amazon
Audible's help says that for Read & Listen (formerly Whispersync for Voice) "you'll need both the audiobook and Kindle eBook in your Audible and Kindle libraries". Immersion Reading is the highlighted version: "the text highlights as the narrator reads".
It is polished and needs no setup. But it pairs only a Kindle ebook with its Audible audiobook, so the files you already have stay on your disk. And it is a reading feature rather than a language tool: a dictionary lookup, but no translation in context and no review of the words you met.
Storyteller: your own files, on your own server
Storyteller describes itself as "a self-hosted platform for automatically aligning ebooks and audiobooks". It's open source, and "all of your books stay on your hardware". You add an EPUB and its audiobook, it aligns them, and you read the result in Storyteller's iOS and Android apps, offline if you like.
What it asks of you is a computer to run it on. Its own requirements are Docker, 8 GB of memory, up to 4 CPU cores and about 1 GB of disk per book. A GPU is optional. The docs say the hardest part of the work is transcription, and that a GPU "can sometimes be a speedup of 10x or greater". They give no processing times, because those depend on your machine. Like Kindle, it's built for reading and listening: we found nothing in its docs about translating words or reviewing vocabulary.
If you already run a home server and want your library to stay on it, Storyteller is a good fit. If you'd rather not install anything, or you're learning a language, read on.
Readuet: your own files, reading along in about 30 seconds
It's fast
You upload the ebook and the audiobook. Readuet transcribes the narration and matches it to the text, so every sentence gets a start and an end time.
That work happens on our servers, not on your phone or a computer you have to set up. There's nothing to install, your battery doesn't pay for it, and a long book doesn't mean a long wait. About 30 seconds after the upload, the opening is ready and the narrator is reading along with you. The rest of the book lines up behind you while you read. If you jump far ahead, the part you land on is timed within moments.
It's your own books
Anything you own as an ebook and an audiobook: a novel in the language you're learning, a book you've read before in translation, the audiobook you never finished. It stays in your library, with your place kept across the browser and the iPhone app.
It's built for learning a language
This is the difference from every reading app:
- The sentence being read is the one that's lit. Press and hold any sentence and choose Play from here to send the narrator there.
- Tap any word you don't know and you get its translation in that sentence, not a dictionary list, in any of 67 languages you translate into.
- Every word you tap is saved with its CEFR level (A1–C2), and in ten major European languages all its forms count as one word.
- Saved words come back for review as spaced-repetition flashcards, and meeting a word again in the book counts too. You stop looking up the same word three chapters in a row.
Why reading and listening together works: what the research says. How to turn it into a routine: how to learn a language with audiobooks.
What it costs
- The free plan includes a library of public-domain classics, with narration and read-along on the ones already prepared, plus tap-to-translate, review, and a few of your own ebooks as text.
- Solo ($4.99 a month or $29.99 a year) adds the audiobooks you own and lines them up with the text when you ask.
- Duet ($7.99 a month or $49.99 a year) gives your own books the live highlight from about 30 seconds after the upload.
Both paid plans start with a free week. Readuet runs in the browser at app.readuet.com and on iPhone and iPad. The Android app is in testing and not out yet.
Step by step
- Sign in at app.readuet.com or in the iPhone app. Uploading needs an account, not a guest session.
- In your library, tap Add book, then Choose ebook and pick your EPUB, MOBI, AZW3, FB2 or TXT.
- Tap Add audiobook now, then Choose audiobook file(s), and select every file of the book at once.
- Tap Upload and process. You can leave the screen: you'll get a notification when the book is ready.
- Open the book and press play. The sentence being read lights up. Tap a word you don't know.
You can also add the audiobook later to an ebook that's already in your library.
Want to try it before uploading anything? Books badged Instant in our free library are already paired and open with their narration on every plan, and this list sorts free books by CEFR level.
Kindle and Audible vs Storyteller vs Readuet
| Kindle and Audible | Storyteller | Readuet | |
|---|---|---|---|
| Which books | A Kindle ebook plus its Audible audiobook | Your own EPUB and audiobook files | Your own ebook and audiobook files, plus a free library |
| Setup | None | Your own server with Docker, 8 GB of memory | None: sign in and upload |
| How fast | Ready when you buy both | Depends on your hardware; a GPU helps a lot | Reading along about 30 seconds after the upload |
| Where your books live | Amazon | Your own hardware | Our cloud, synced across your devices |
| Unknown words | Dictionary lookup | Not covered in its docs | One tap: translation in context, saved, reviewed later |
| Built for | Reading and listening | Reading and listening | Learning a language |
| Where you read | Audible and Kindle apps, Fire tablets | Storyteller's iOS and Android apps | Browser, iPhone and iPad |
| Cost | You buy both halves | Free software; you run the server | Free library; your own audiobooks from $4.99 a month |
Frequently asked questions
How long does it take before I can read along?
About 30 seconds after the upload finishes, with Duet. Readuet aligns the opening first so you can start, and lines up the rest of the book while you read. The alignment runs on our servers, so your phone does no heavy lifting.
How is Readuet different from Storyteller?
Both line up your own ebook with your own audiobook. Storyteller runs on a server you set up, keeps everything on your hardware, and takes as long as your machine needs. Readuet runs in our cloud with nothing to install, has you reading along about 30 seconds after the upload, and is built for learning a language: tap a word for its translation in context, and it comes back for review.
Does the ebook have to be the same edition as the audiobook?
Yes. Small differences like a preface or a narrator's introduction are absorbed. An abridged recording, a different translation or a dramatisation won't line up, however long the processing runs.
My audiobook is 40 MP3 files. Is that a problem?
No. Select them all at once when you add the audiobook; they play in filename order, so files numbered 01, 02, 03 come out in the right order. A single M4B works too.
Which languages can I read in?
Dozens, for the book and for the language you translate into: there are 67 to translate into. Grouping every form of a word under one dictionary form covers ten major European languages. Chinese, Japanese and Korean aren't supported yet, and neither is PDF.
Can I do this for free?
You can read along for free with the prepared books in our public-domain library. Pairing your own audiobook needs Solo or Duet, and both start with a free week.
Does reading while listening actually help you learn a language?
Studies of reading while listening found gains in vocabulary, comprehension and reading fluency, with some limits. We went through them in what the research says.