Read real books in a new language — tap any word to understand.

The format

Simple enough to read by hand

A .tbook is a ZIP of JSON: a manifest, a language-free text skeleton per chapter, and one gloss overlay per chapter and language. Here is the shape of the data.

• sentence ranges in the paragraph text
• translation text, per language
• links from translated words to source words
• inline emphasis (italic / bold)
• per-paragraph roles

text stores each paragraph once; sents are ranges into it, and the tappable words come from the shared tbook-w2 tokenizer. In the gloss overlay, t is the translation and a gives every translated word the index of the source word(s) it renders — exactly what lights up when you tap.

Adding a language appends one overlay per chapter without touching the text. The optional spans and role add inline emphasis and paragraph roles; readers ignore fields they do not recognize, and digests reject an overlay that no longer matches its text.

{
  "id": "cd0f91ee6",
  "paragraphs": [
    { "id": "eb7f661e", "role": "heading",
      "text": "Prologue", "sents": [[0, 8]] },
    { "id": "a732da8b", "role": "subtitle",
      "text": "Cerberus, Delta Pavonis", "sents": [[0, 23]] },
    { "id": "e3b0c442", "role": "sceneBreak",
      "text": "", "sents": [] },
    { "id": "4ee30ecc",
      "text": "Stan went to the living room.",
      "sents": [[0, 29]],
      "spans": [{ "s": 17, "e": 28, "k": "i" }] }
  ]
}