Translation & CAT Tools

Authors getting books into another language reach for one of two paths: MT (machine translation) + paid human edit (cheap, fast, OK quality) or a CAT — Computer-Assisted Translation — tool with translation memory (slower, but reuses every sentence you've ever translated). For docs / app i18n see i18n; for AI-assisted drafting see writing-ai-assistants.

Machine translation (MT)

• ★ DeepL — paid + free Lite; ★ for literary / nuanced text; consistently beats Google Translate on European languages; free tier covers small projects; Pro adds glossary + document translation + privacy mode.
• Google Translate — free; the broadest language coverage; less-good prose quality.
• Microsoft Translator — free + paid; broad; document translation.
• Reverso — free + paid; great context examples / synonyms.
• LibreTranslate — AGPL; free OSS; self-hostable Argos Translate-based; privacy-respecting MT for sensitive manuscripts.
  • https://github.com/LibreTranslate/LibreTranslate
• Argos Translate — MIT; free OSS; offline desktop MT; fully local.
• NLLB / SeamlessM4T (Meta) — open weights; for self-host MT pipelines.

CAT tools (translation memory + glossary)

• ★ OmegaT — GPL; free OSS; Java; cross-platform; ★ the FOSS CAT default. Translation memories (TMX), glossaries (TBX), supports docx / ODF / HTML / XLIFF / SRT. Less polished than Trados but free and capable.
  • https://github.com/omegat-org/omegat
• ★ MateCat — LGPL; free OSS + free hosted SaaS; web-based; integrates DeepL + Google + ModernMT pre-translation; collaborative.
  • https://github.com/matecat/MateCat
• Smartcat — paid + free; web; CAT + marketplace for freelance translators; popular with authors hiring out.
• Trados Studio — paid (~$700+); Win-only; the pro-translator industry standard; dominant in agencies; overkill for most authors.
• memoQ — paid; pro CAT; popular Trados alternative.
• Crowdin / Lokalise / Transifex — paid; for software / app localization rather than book translation.

AI-assisted translation (2024-26)

• DeepL Write — paid + free Lite; rewrite / polish in target language.
• GPT-4 / Claude / Gemini — paid; literary translators increasingly use LLMs for first-pass translation, then a human-translator edit pass. Quality varies wildly by language pair — Japanese-English literary is famously hard. See ai-llm.
• Sudowrite — paid; has a translation feature; flagged-as-controversial in literary translator circles. See writing-ai-assistants.

Working with human translators

• Reedsy — see writing-self-publishing-kdp; vetted literary translators.
• PEN America Translation Database / Words Without Borders — free directories of literary translators.
• ProZ / TranslatorsCafe — paid + free; pro-translator marketplaces.
• Smartcat marketplace — paid; built into the CAT tool.

Glossary / terminology management

• Translation memory (TMX) — open standard; portable across CAT tools.
• Term Base eXchange (TBX) — open glossary format.
• TermWiki / IATE (EU termbase) — free terminology references.

Subtitle / caption translation

• See video-subtitles and video-auto-captions-whisper.

Pick this if…

• Quick paragraph / sentence: DeepL (free).
• Self-hosted private MT: LibreTranslate or Argos Translate.
• Free CAT for hobby / self-translation: OmegaT.
• Web CAT with MT integration: MateCat.
• Pro agency work: Trados or memoQ.
• Hire a literary translator: Reedsy or Smartcat marketplace.