DualBook 8 languages

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Make an English-Thai bilingual book

Each English paragraph with its Thai translation directly beneath it, in one EPUB. Read the English first; the Thai is there for the sentence that will not resolve.

The first 15 pages of text are sent to our server to be translated. The file itself stays on your device.

For a Thai reader learning English, the sticking point is usually not a word but a tense. Thai does not mark time on the verb, so English's constant insistence on it — had gone, has been going, would have gone — is a grammar with no counterpart to map onto. Rules do not fix that; repeated exposure to the same sentence in both languages does, because you see what the Thai establishes once and the English repeats in every verb.

Your browser opens the EPUB, walks each paragraph and inserts the Thai beneath it as a sibling paragraph inside the original file. Only the chapter documents that receive a translation are rewritten, so cover, navigation, stylesheet and metadata survive as they were.

The inserted paragraphs are styled to wrap rather than overflow, which matters more here than in most pairs: Thai has no spaces between words, so a long run of text is, to a simple layout engine, one enormous word.

How it works

  1. Choose an English EPUB

    A DRM-free EPUB. The bilingual file is assembled in your browser, not on a server.

  2. The model reads the whole book

    The cast, their genders and their relationships are mapped once, so pronouns and particles stay consistent.

  3. Thai is inserted under each paragraph

    Each translation is styled beneath its paragraph and set to wrap, so a spaceless Thai run cannot push the page sideways.

  4. Read it here, or on any device

    A complete EPUB carrying the book's own fonts and stylesheets.

The trap, and the honest limits

Your eye will go to the Thai. Read the English paragraph first, every time. The seconds of not understanding are the practice; skipping them means finishing a whole book having learned very little.

Line breaking depends on your reader. Breaking Thai correctly requires the device to know where words end. Recent readers do; older ones can break mid-word. That is the device, not the file.

Fifteen pages get translations. The rest of the book stays in English inside the same file.

The text is sent to a server and discarded when the job ends. The file never leaves your device.

Questions

Which side should I read first?

English first, every paragraph. Sit with the confusion for a moment before you look down — with this pair the moment is usually a tense clicking into place, which is worth more than a looked-up word.

Why is the Thai written without spaces?

Because that is correct Thai. Spaces in Thai end a clause, not a word. A file that put spaces between Thai words would be wrong in a way every Thai reader notices immediately.

Will it open on a Kindle?

Yes. Kindle has accepted EPUB directly since 2022 and renders Thai; email the file to your device or copy it across.

Do the cover and table of contents survive?

Yes. The browser rebuilds the archive entry by entry and only rewrites the chapter files that received a translation, so everything else passes through untouched.

The whole book, in parallel

The app builds the bilingual version of the entire book, with tap-to-look-up and your reading position synced across devices.

Open DualBook