TReader: offline tbook reader

TReader is an offline tbook reader that turns reading into the most natural way to learn a language. Read a real book in the language you're learning, and whenever you reach a word you don't know, just tap it — TReader instantly shows the whole sentence translated, with the matching word highlighted so you can see exactly what it means in context. No dictionary detours, no switching apps, no losing your place.

Because every translation is built into the book itself, reading works completely offline. There's no account to create, no ads, and no tracking. The only thing TReader ever downloads is an optional offline dictionary, when you ask for one. Your books and your reading progress never leave your device.

HOW IT WORKS
• Read the original text at your own pace.
• Tap any word to see its full sentence translated, with the corresponding word(s) highlighted.
• For English texts, you also get the word's IPA pronunciation.
• Close the panel and keep reading — your position is always saved.

FEATURES
• Fully offline reading — no account, no ads, no data collection; the network is used only to fetch an optional dictionary.
• Sentence translation with word-level highlighting, so you learn words in real context.
• IPA pronunciation for English source texts.
• Offline dictionaries — install a dictionary for your language pair and open full articles straight from the word popup.
• Read aloud — hear any word or sentence via your device's text-to-speech.
• E-ink mode — black-on-white, no animations, volume-key page turns; auto-detected on e-readers and switchable by hand.
• Built-in library; import your own books in one tap.
• Tune your reading: Serif, Sans, or Mono fonts, adjustable text size, and custom page margins.
• Light, Dark, and System themes.
• Scroll or Paged reading modes.
• Books with more than one translation language include a quick language switcher.
• A complete book is included — The Adventures of Sherlock Holmes, with translations into eight languages — so you can start reading the moment you open the app.

PRIVACY FIRST
TReader collects nothing. It contains no analytics or advertising and keeps your library and reading positions only on your device. Its single network request is downloading a dictionary you chose to install — a plain file download that carries no identifiers. What you read is your business.

THE TBOOK FORMAT (.tbook)
TReader reads tbook — an open, offline-first ebook format made for language learners, whose files carry the .tbook extension. It is what makes the tap work:
• Translations and word alignment are baked into the book when it is created, so every tap answers instantly, with no network and no API calls.
• Alignment is word-level, not just sentence-level: each source word points to the exact word(s) it becomes, even when the translation reorders the sentence.
• One file, many languages: the original is the pivot and every translation aligns back to it, so you can switch translation language inside the same book.
• Open and inspectable — a .tbook is a ZIP of plain JSON. No DRM, no proprietary blobs, no lock-in; the specification is public at tbook.dev.
• Versioned and additive, so today's app keeps opening tomorrow's books.

GETTING BOOKS
Sherlock Holmes is built in. To add your own, convert an EPUB or FB2 file at convert.tbook.dev and import the tbook file it gives you. Or do it yourself: the converter is free and open source — download it from tbook.dev and run it on your own machine with your own translation API key.

Happy reading — and happy learning.