Smart Book alternatives
for learners who want to listen first
Smart Book by KursX is a bilingual e-book reader for people who want to read real books with a translation one tap away. It is built around the text: parallel translation, many translators and AI tools, and a vocabulary builder. If you would rather learn mostly by listening, with the phone in your pocket, a different kind of app may suit you better.
What Smart Book is and does well
Smart Book is a bilingual e-book reader for Android and iOS. You read in the original and bring in a translation when you need it: tap a word for a context-aware translation, long-tap a sentence, paragraph or chapter, or show a paragraph's translation directly under it, manually or automatically.
- Content. A built-in library of more than 75,000 books in many languages, with new titles every week; classics can be browsed by level from A2 to C2. Some books come with a published translation, which you can swap for a machine one. You can import your own EPUB, FB2 and TXT books, turn .srt subtitles into a parallel book, or build one from any text.
- Translators. Google Translate, DeepL, Microsoft, Yandex, Reverso Context, ChatGPT, Claude and Gemini, a screen for comparing them, and a downloadable offline translator. Around 100 languages.
- AI tools. Definitions, etymology, examples and grammar breakdowns sit in the translation panel, alongside your own AI actions. Paid plans unlock contextual AI translation and custom actions, or you can connect your own API key for ChatGPT, Claude, Gemini, DeepSeek and other services.
- Vocabulary. Save words with the sentence they came from, review them with spaced repetition, sync with Anki or ReWord, and export to Excel or TXT (a paid feature).
- Audio. Tap any word or passage to hear it. The Narrator reads paragraph by paragraph in a sequence you set, for example paragraph, translation, paragraph again, with player controls and automatic continuation into the next chapter. The voice comes from the phone's speech engine; AI voices from ElevenLabs, OpenAI, Google, Microsoft, Speechify or Amazon come through Tetsy, a separate KursX app on Google Play that uses your own API key or tokens bought in that app. With Tetsy, a chapter can also be saved as an audio file.
- Pricing model. Free to use, with ads and a limit on online translation. A one-time PRO purchase and a MAX subscription unlock more; inviting friends or a one-day trial can unlock paid features at no cost.
Smart Book is at its best for readers who want control: their own books, their choice of translator, their own AI prompts and a vocabulary pipeline into Anki. In January 2026 the developer wrote that the iOS app would come close to the Android version over the year.
Where Smart Book users look for something different
In Smart Book, audio is a layer on top of the text. The Narrator voices whatever is open with a speech engine you choose and configure. That flexibility is the point, but the listening setup is yours to assemble: engine, voice, perhaps a synthesis app and a provider account.
The help is organised around the screen too: tap a word, slide the translation panel up, choose an action, read the answer. That suits the sofa more than a walk, the gym or a commute with the phone in a pocket.
Smart Book users who look elsewhere usually want:
- to learn mainly by ear, with every sentence of a book already narrated rather than set up per device;
- explanations spoken to them at their level while the story keeps going;
- to ask about a word or a plot point out loud, without taking the phone out.
Redible — how it differs
Redible is built so that listening is as comfortable as reading. Every sentence of each complete book is narrated in a natural, expressive synthesized voice (not a human narrator, and not the phone's built-in speech engine) and synchronized with the text, so you can read along or put the phone away.
- Sandwich mode plays the original sentence, then the same sentence in your language, then the original again.
- Hints (short explanations on the words likely to be new at your level) and sentence translations on request are spoken as well as shown.
- Hands-free AI: tap your earbuds or the lock-screen button and ask out loud what a word meant, what just happened or why a character did something. You hear the answer, the book continues, and the screen can stay off. You can also type or tap a suggested question.
- Auto mode sets how often support appears, which hints play and how fast the narration runs, based on the level you choose (A1–C2).
- With Premium, downloaded books and audio work offline. Playback continues in the background with lock-screen controls, the book and support voices have separate speeds, and your position syncs across devices.
The trade-offs: books are in the original language, not bilingual editions, from a curated library rather than an open catalogue. Book languages are English, French, German, Italian, Portuguese, Russian and Spanish, on iPhone, iPad and Android. It is free to start, with the first chapter of every book fully voiced and supported; Premium is $11.99 a month or $99.99 a year on the US App Store.