How to Set the Language of a PDF
Standards this affects
- PDF/UA — ISO 14289-1, clause 7.2 (natural language)
- WCAG 2.1 — 3.1.1 Language of Page (Level A)
- Section 508 — 504.2 / WCAG 2.0 AA by reference
What this means
A PDF should declare its primary natural language (e.g. English, French) in the document catalog. Passages in a different language should declare their own language on the relevant tags.
Why it matters
Screen readers switch pronunciation rules and voices based on the declared language. An English document with no language set may be read by a French synthetic voice — or with the wrong intonation — making it hard or impossible to understand. Setting the language is a quick, mandatory fix.
How the checker flags it
- The checker reports "language not set" or "primary language missing".
- Acrobat's checker flags "Primary language" under Document.
- A screen reader mispronounces words or uses the wrong voice/accent.
How to fix it
- 1
Set the primary language in Acrobat Pro
Open File → Properties → Advanced tab. Under "Reading Options", choose the document's language from the Language dropdown (or type a language code).
- 2
Mark language changes within the document
If a section, quote, or phrase is in another language, select its tag in the Tags panel, open its Properties, and set a Language for that element so screen readers switch voices correctly.
- 3
Set language at the source
In Word, set the proofing language (Review → Language → Set Proofing Language) for the document and for any foreign-language passages before exporting. It carries through to the PDF.
Check your PDF for this issue
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Frequently asked questions
- Which language code should I use?
- Use a standard language tag such as "en" (English), "en-US" (US English), "fr" (French), or "es" (Spanish). Acrobat offers common languages in a dropdown; for others you can type the code directly.