How to use Duolibri

Basic Principles

  • Duolibri is intended for intermediate or advanced language learners.
  • Read books that you have already read in your native language, preferably books that you enjoy.
  • Read for extended periods of time. Avoid stopping and starting as much as possible.

How to Use Duolibri

Here is a typical sequence of learning steps:

  1. Read the book in your native language (right-hand) so that you know the story (either in DuoLibri or in another app or on paper)
  2. Listen to the audio while reading along in your native langague
  3. Listen to the audio while reading along in the foreign (left-hand) language. Even if you don't understand the words, the goal is to be able to separate the speaking into words and phrases and get used to hearing the language at normal speed.


Some people do steps 2 and 3 in a different order or multiple times. Most people that have described this learning method agree on these techniques:

  • Use books you like & enjoy (this really helps). Or that you are highly motivated to read (e.g. because you have to read it for a course).
  • Using longer texts is key to learning. There will be lots of things you don't understand but as you spend time with it, you will pick up more and more. The books are long enough that you will hear most words more than once.
  • Rather than stopping and starting a lot, it's better to listen to the whole book or individual chapters multipe times. Treat it as an immersion experience, like if you were listening to people speaking in the new language. Since you should already know the basic story and context, you won't be totally lost like you would be if you were listening to the radio or watching TV in the foreign language.

Generally you want to get to the point where you're not looking at any text in your native language while reading. You want to be immersed and start thinking in the foreign language.

The method of reading and listening to long novels in order to learn languages has been called the "Listening-Reading Method". See the "desciption of method" section below in the FAQ for more info.

How to avoid getting lost while reading

Here are some ideas to make reading the books easier:

  • Make sure you already know the story. Read the book or chapters first in your native language. The better you know the story, the better this method will work.
  • Concentrate on the plot of the story and not on individual vocabulary or grammar points.
  • The first few chapters will be much harder since you need to get used to the sound and style of the language and the specific speaker (their idiolect). Keep going!
  • Use the professional translation on the right side to understand what is going on.
  • Turn on the embedded grammar and/or the embedded phrase translations to aid you while reading (without having to stop the audio).
  • Use the dictionary to figure out sentences in detail (while the audio is stopped.)

Frequently Asked Questions

Duolibri is aimed at intermediate and advanced learners of a language. You'll need to know basic vocabulary and be able to read some sentences.

Choose a book that you like and that you've already read in your native language. This will make it easier to follow along and make and make the experience more enjoyable. If the book is too hard, see the answers to some of the other questions here for some tips.

If you're having trouble understanding a book, here are some things to try:
  • Turn on the embedded translations.
  • Turn on the embedded grammar. Make sure you're familar with key verbs (like "to be" and "to have" in the tenses being used in the book).
  • Re-read the book (or some chapters) in your native language before trying again in the foreign language.
  • Consider some getting more familiar with some of the language basics. (See below for some apps recommended for beginners.)

Duolibri is not intended to be an app for beginners. There are now many good language learning apps, for example: Duolingo, Fluent Forever, Memrise, and many other apps.

While you can read the book in text or listen to the audio alone, Duolibri isn't the ideal app for that. There are many great e-reader and audiobook apps for all types of devices. The book texts are available on Project Gutenberg and the audiobooks on Librivox Many of the apps allow you to get the books directly from places like Project Gutenberg from within the app. Some of the apps that I use are eBoox (Android) and KyBook (iOS), but there are many others.

There are some great apps that offer parallel text and synchronized audio for shorter texts - Beelinguapp is a very nice recent one.

You may wonder why we need to charge for books since in many cases the book text and audio are freely available. The reason is that creating, testing, and maintaining the software is a lot of work. Preparing each book for Duolibri is also time consuming and incurs costs to generate the grammar and in-line translations using external services. Running the web sites and serving up the files has monthly costs. Keeping the apps up-to-date and working with the app stores is an ongoing battle.

We don't run advertising. We don't collect information on you. We don't sell information. Our business is simple: we provide enhanced multi-language book services and we charge for them.

I'm hoping that the services provided by Duolibri offer a lot of convenience. In my opinion, Duolibri should feel like an incredible value (I invested years of work in this and I get a lot of value from it every time I use it).

If you would like to see a book added to Duolibri, send me a message via the Contact page. I'm keeping a prioritized list of the next books to add. At this point this needs to be a book that is in the public domain - look on Project Gutenberg and Librivox. In the future, I would love to add some more recent books but I will need to reach agreements with the owners of the book rights. Let me know if you have an connections that could help make this happen!

Creating an embedded dictionary has been a lot more difficult than I expected. Here is what I was looking for:
  • Comprehensive definition (not just single word translations) in the foreign language. At the intermediate/advanced level, one should be getting used to using dictionaries in the foreign language (at least that's what my professors kept telling me).
  • Able to embed the dictionary with the book and stored locally on the device (i.e. no internet connection needed).
  • Able to see definitions for mulitple words open at the same time (for when you're tring to understand a tricky passage).
The current definitions are taken from Wiktionary and are not bad but are not as good as I would like. I have added buttons to go to the full Wiktionary entry as well as to a single word Google translation.

Currently you can select a slower speed in the web browser version of the Duolibri reader. This is not currently supported in the Android and iOS versions of the reader. This is something that I would like to add but the software I'm currently using doesn't support it. Keep in mind that one of the goals is to get used to hearing the language at a normal speed. Since we're reading full boooks here, if you miss some words or sentences, that's OK, it's best to keep going and gradually learn as you get through the book.

The method of reading and listening to long novels in order to learn languages has been called the "Listening-Reading Method". Search in Google for "Listening-Reading Method" to find lots of resources. I first came across a description of the method and was inspired by this epic post/thread. There is huge discussion there if you want to geek out.