Reading in a foreign language produces vocabulary. But vocabulary only sticks if it is captured and reviewed. The best apps for translating words from books combine reading, translation, and vocabulary saving into a single workflow - so the words you look up do not disappear when you close the app.

What to Look for in a Book Translation App

Not all reading apps are equal for language learning. The features that matter:

  • Inline translation: translate any word with a single tap without leaving the book
  • Automatic word saving: looked-up words are captured to a vocabulary list without manual action
  • Review system: saved words are reviewed via flashcards, push notifications, or spaced repetition
  • Format support: handles EPUB and PDF, the two most common ebook formats
  • Language coverage: supports the language you are learning

Apps that have all five are rare. Here are the best options across the spectrum.

TransLearn

TransLearn is built specifically for this workflow. Import EPUB or PDF books, tap any word for translation in 120 languages, and words are saved automatically to your vocabulary list. Push notifications review saved words throughout your day using spaced intervals.

The key advantage over general ebook readers is the complete pipeline: read, translate, save, review - all in one app. No exporting, no separate flashcard app, no manual copying.

Best for: learners who want reading and vocabulary review in a single app across many languages.

LingQ

LingQ highlights every word in your imported text based on whether you have seen it before. Unknown words are shown in blue. Words you have studied are shown in yellow. Known words are shown without highlighting. You build a statistical picture of your vocabulary as you read.

Click any word for its definition and a list of example sentences. LingQ has a large community library of reading content for many languages, so finding graded material is easy.

Best for: learners who want detailed vocabulary tracking and a structured content library.

Readlang

Readlang is a browser extension and app that translates words and phrases on any web page or imported text. Saved words are automatically converted into flashcards for spaced repetition review.

Best for: learners who read a lot of foreign language content online and want automatic flashcard generation from their reading.

Kindle With X-Ray and Dictionary

Kindle's built-in dictionary feature allows word lookups within books, and the X-Ray feature provides character and concept information. For supported languages (primarily English, Spanish, French, German), the Kindle dictionary lookup is fast and usable.

Limitations: vocabulary saving to a review system is limited, and language coverage for translation is narrower than dedicated language learning apps.

Best for: casual readers who want occasional lookups but are not building a systematic vocabulary practice.

Anki Integration Workflow

Some learners use a two-app workflow: a reading app for lookup and Anki for review. Many reading apps allow word export, and Anki's spaced repetition algorithm is among the most powerful available.

The limitation is friction: exporting words, formatting Anki cards, and maintaining two apps adds steps that many learners eventually stop doing.

Best for: dedicated learners comfortable with technical setup who want maximum review customization.

The Recommended Workflow

For most language learners, a single app that handles reading and review together is more sustainable than a multi-app pipeline. TransLearn or LingQ both offer this. The choice comes down to whether you want to import your own books or use a curated content library.

Whatever app you choose, the habit matters more than the tool. Read something in your target language every day, tap words you do not know, and let the app's review system handle the rest.