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Localization

A book in seven parts on making software speak other languages: what a locale is, how a program is prepared for translation, which files carry the words, how terms are chosen and remembered, how an interface is translated well, what a translation engine can and cannot do, and how the whole thing ships without regressing. It condenses nine published books on internationalization and localization written between 1993 and 2025, a 2026 research corpus on Qt, web and model-driven localization, the engineering specification of the fl10n toolkit, and the practice of the FontLab localization into German, Spanish, French and Polish. The book documents the reasoning behind vexy-localizzy, the localization toolkit that grew out of that work, but it is written for any team that ships text.

The seven parts, and the toolkit

  1. Foundations. Locales, encodings, formats, plurals, scripts, space and cost: the facts every other part assumes.
  2. Engineering. Preparing code for translation: externalized strings, placeholders, the Qt and web toolchains, mirroring, rendering and world-readiness tests.
  3. Formats. Qt TS, gettext PO, XLIFF, JSON, Android, Apple, TMX and TBX; the canonical model, conversion, byte-preserving edits and message identity across versions.
  4. Terminology. Glossaries, the fallback original term, core and project memories, evidence-based term choice, the house voice across languages, word formation and the ledger.
  5. Interface. Translating compact strings: headline style, no added detail, mnemonics and keys, plurals, placeholders, registers, source defects and review in the running application.
  6. Machine translation. From rule-based systems to language models; context, memory-first pipelines, glossary enforcement, the placeholder protocol, routing and cost, quality estimation, post-editing and trust.

  7. Process. Continuous localization, branches, the quality gate, linguistic quality assurance, pseudo-localization, review tools, vendors, content beyond the catalog, release and provenance.

  8. The toolkit. The reference documentation of the vexy-localizzy package: commands, memories, upgrades, formats, QA, extraction, review and the corpus.

Each part opens with a short chapter on what it covers and how its chapters connect. Chapters end with the sources they drew on.

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