Comparison

duoBooks vs Readlang Mobile

Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.

Head to head
About

duoBooks

Read any book in any language with instant translation and detailed word explanations. Build your vocabulary with a personal dictionary and spaced repetition tools. Improve pronunciation with audio voiceovers and master new languages through immersive bilingual reading.

Highlights
  • Instant translation of any book
  • Personalized vocabulary dictionary
  • Spaced repetition for memorization
  • Audio voiceovers for pronunciation
  • Bilingual parallel text reading
  • EPUB reader for custom files
Features
Read full description

Read any book in any language with instant translation into your native language. We offer short stories designed specifically for beginner language learners. Alternatively, you can add any book from your device and read with translation whatever you want. Break any sentence into clear pieces and see every word explained in context. Instantly understand how the sentence works, what each word means, and how it fits into the full translation. In our app, you will also have your personal dictionary where you can keep your vocabulary in one place and easily review it whenever you want. Mastering correct pronunciation is key to language acquisition. In our app, you can listen to audio voiceovers of every sentence or word to hear it pronounced accurately. Immerse yourself in language learning with ease. To learn words, we provide a Spaced Repetition tool. With it you can review words at increasing intervals, ensuring long-term retention and mastery. Swipe through word flashcards effortlessly to build a robust vocabulary and make memorizing words a seamless part of your daily routine. Build your English vocabulary. Many people who are not native English speakers use our app as epub reader to read scientific materials or programming books in English. As long as you have an EPUB file for what you want to read, our app is the best choice. Our bilingual book reader is designed to enhance your language proficiency one page at a time. Practice and study foreign languages by reading parallel texts where every sentence is translated into your native language. Reading books with translation is a proven method for language learners to improve their reading comprehension, expand their vocabulary, and gain a deeper understanding of grammar structures. Read with translation any EPUB ebook from your device, or choose from our library with 3000+ books and short stories. Reading enhances your creativity, imagination, and empathy. Moreover, reading has been shown to reduce stress, improve mental health, and increase our overall well-being. Dive into a world of dual-language storytelling. Don't just take our word for it - hear what our users have to say: "This app has revolutionized my language study! I use it with my own EPUB files in a language I am studying. The interface is intuitive. It's also very fast to use and provides a smooth experience during long reading sessions." Read in English, German, French, Spanish, Italian, or any other language, build your vocabulary, and improve your grammar skills. With our cross-language ebook reader, translate books on the fly and listen to voiceovers of any sentence or word in your book. Best bilingual reading app available. With duoBooks you will: - Take control of your language learning journey and achieve your goals faster and easier than ever before. - Improve speaking by listening to how words and phrases are pronounced correctly. - Easily incorporate reading into your daily routine and reap the numerous benefits of this powerful skill, all while you learn English (or other languages). - Read English books with translation (or Spanish, French, etc.) easily even if it's not your native language. - Study words with scientifically proven technique (Spaced repetition). Swipe word cards and enjoy the process. Smart Interval system is as effective for memorizing words as English lessons. duoBooks offers short stories specifically created for beginners. They use simple vocabulary, repetitive words, simple dialogues, and uncomplicated sentences. Alternatively, we have a vast selection of classic literature. From the works of Edgar Allan Poe to the novels of Jane Austen. With over 3000+ classic ebooks available and the ability to import your own files, you'll never run out of options to practice your language skills. Whether you're a beginner or an advanced learner, duoBooks is your app for language learning success. Start your journey today with our free language learning app!

About

Readlang Mobile

Features
Read full description

Readlang Mobile Readlang Mobile helps you learn languages naturally by reading real content you actually enjoy — books, articles, and websites. Tap any word or phrase to see an instant translation without breaking your flow. Save new words, track your progress, and build vocabulary effortlessly while reading. Key Features: • Instant word translation while reading • Phrase translation support • Save and review translated words • Clean, distraction-free reading experience • Reading statistics and progress tracking • Read websites and books directly in the app Free Plan: • 30 translations per day • Phrase translations (up to 6 words) • Access to all books and websites in the app • View basic reading statistics Premium Features: • Unlimited translations • Phrase translations (up to 12 words) • Upload and read your own EPUB books • Multiple-choice vocabulary practice • Full access to advanced reading tools Subscription Information: Readlang Mobile offers auto-renewable subscriptions: • Monthly subscription • Yearly subscription (save with annual billing) Prices may vary by location and are shown in the app. Payment will be charged to your Apple ID account at confirmation of purchase. Subscriptions automatically renew unless auto-renew is turned off at least 24 hours before the end of the current period. You can manage or cancel your subscription anytime in your Apple ID account settings. Legal: Terms of Use: https://readlang-mobile.com/terms Privacy Policy: https://readlang-mobile.com/privacy Contact: Support: support@readlang-mobile.com Website: https://readlang-mobile.com

Screenshots

duoBooks4 screens
Readlang Mobile4 screens

Verdict

The call

The clearest difference is review sentiment: Readlang Mobile at 100% against duoBooks's 69%. duoBooks's advantage is rating (4.7 vs 4.3) and ratings volume (48 vs 3). On price, update cadence, ads and in-app purchases there is nothing between them.

Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS

CostPrice · In-app purchases · Ads · Monetization

Both are free to download. duoBooks sells 11 in-app purchases, starting at $2.99 per month and Readlang Mobile sells 2 in-app purchases, starting at $6.99 per month. Whichever you choose, the download price is not the number that matters.

ReceptionRating · Positive reviews · Number of ratings

duoBooks holds the better App Store score, 4.7 against 4.3. That said, the two scores are not equally well evidenced: duoBooks has 48 ratings behind it against 3, so its average is the more settled of the two. Written reviews complicate that: 69% of duoBooks's written reviews are positive against 100% of Readlang Mobile's, so the app with the better star average is not the one people write more warmly about.

UpkeepUpdate frequency

duoBooks ships an update every 2 weeks, Readlang Mobile every 6 days. The most recent releases landed on September 21, 2026 and September 24, 2026 respectively.

Scorecard4 real differences · 6 level
duoBooks versus Readlang Mobile: the parameters behind the verdict, then further details
ParameterduoBooksReadlang Mobile
PriceFreeFree
Rating4.7 (48 ratings) — better4.3 (3 ratings)
Positive reviews68.6% of reviews100.0% of reviews — better
Number of ratings48 — better3
Update frequencyEvery 2 weeksEvery 6 days — better
AdsNoNo
In-app purchasesYesYes
MonetizationFree with in-app purchases—
DevicesiPhone, iPad, iPod — betteriPhone, iPad
Requires iOS15.0 — better18.0
Further details — not scored
Size54 MB35 MB
Age rating12+17+
DeveloperPlainProg LLCAlisher Fayzullaev

Customer experience

duoBooks

All ratings48 ratings
Positive93.8%
Neutral0.0%
Negative6.3%
Written reviews35 reviews
Positive68.6%
Neutral11.4%
Negative20.0%

Readlang Mobile

All ratings3 ratings
Positive66.7%
Neutral33.3%
Negative0.0%
Written reviews2 reviews
Positive100.0%
Neutral0.0%
Negative0.0%

In-app purchases

11 purchases

duoBooks

Subscriptions5
  • Full Plan7 Days trial$2.991 Month
  • Full Plan3 Days trial$6.991 Month
  • Full Plan7 Days trial$17.991 Year
Show 2 more
  • 6 Month Full Plan3 Days trial$19.996 Months
  • Full Yearly Plan3 Days trial$29.991 Year
One-time6
  • War and Peace$0.99
  • Silver Blaze$0.99
  • On The River$0.99
Show 3 more
  • Clochette$0.99
  • The Fishing Hole$0.99
  • Alice in Wonderland$0.99
2 purchases

Readlang Mobile

Subscriptions2
  • Readly Premium Monthly$6.991 Month
  • Readly Premium Yearly1 Year trial$39.991 Year

Questions

Is duoBooks free?
duoBooks is free to download, with in-app purchases available.
Is Readlang Mobile free?
Readlang Mobile is free to download, with in-app purchases available.
Which has better reviews, duoBooks or Readlang Mobile?
duoBooks is rated higher. duoBooks averages 4.7 out of 5 from 48 ratings, while Readlang Mobile averages 4.3 from 3 ratings.
Do duoBooks or Readlang Mobile have ads?
Neither duoBooks nor Readlang Mobile shows ads.
Which is updated more often, duoBooks or Readlang Mobile?
duoBooks ships an update every 2 weeks, and Readlang Mobile every 6 days. Most recently, duoBooks was updated on September 21, 2026 and Readlang Mobile on September 24, 2026.

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