UA1 Validator / PDF/UA-1 rules / 7.2-33

PDF/UA-1 · CLAUSE 7.2

Natural language is not declared

Text in the document, or in an Alt, ActualText, E, Contents, or TU entry, has no determinable language, or the Lang value is not a valid RFC 3066 language tag.

Rule 7.2-33 ISO 14289-1 Object: XMPLangAlt

Why it matters

A screen reader pronounces text using the wrong voice and pronunciation rules, which can make content unintelligible, especially for multilingual documents.

How to fix it

  • Set the document language in File > Properties > Advanced > Reading Options > Language.
  • Mark passages in another language by setting Lang on the enclosing structure element.
  • Use valid tags such as en, en-US, or cs-CZ: a free-text value like 'English' fails validation.
WCAG 3.1.1 Language of Page (A) WCAG 3.1.2 Language of Parts (AA)

What the standard says

Natural language for document metadata shall be determined

Check your own PDF

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Open the validator Automate in CI 
curl -sS -X POST "https://api.ua1.dev/api/validate?format=compact&profile=ua1" \
  -F "file=@document.pdf"