Language is the setting people forget because sighted readers never see it. A screen reader user hears it immediately: French read with English rules is unintelligible, and a Spanish quotation inside an English report is mangled unless the passage is marked. This guide covers the two WCAG techniques for PDF, the five PDF/UA conditions, and the practical handling of documents that mix languages.
The document language
WCAG technique PDF16 describes "setting the default language using the /Lang entry in the document catalog of a PDF document". This is the sufficient technique for success criterion 3.1.1, Language of Page, at Level A, and the same requirement appears in the European standard as clause 10.3.1.1 for non-web documents. In Acrobat it is Document Properties > Advanced > Reading Options > Language; Adobe's checker reports a missing value as Primary language and can set it from the checker. In Word, set the proofing language before exporting. In generated PDFs, it usually comes from <html lang> or a metadata option. The value is a language tag such as en, en-GB, fr-CA, or de; Adobe notes that a language not in Acrobat's list must be entered as its ISO 639 code.
Passages in another language
Success criterion 3.1.2, Language of Parts, at Level AA requires that the language of each passage or phrase that differs from the document be programmatically determinable. WCAG technique PDF19 describes doing this with a Lang entry on a structure element, and gives the Acrobat procedure: select the text, use Create Tag From Selection in the tags panel, open the new tag's properties, and choose the language on the Tag tab. Any structure element can carry a Lang entry, so a Span inside a paragraph handles a quoted phrase while a Sect or Div handles a whole section. Proper names and words that have entered the document's language do not need marking.
The five places PDF/UA checks
PDF/UA-1 goes further than WCAG because a PDF carries text in places other than the page. Matterhorn checkpoint 11, Declared Natural Language, lists five machine-decidable failure conditions, all derived from clause 7.2 of ISO 14289-1:
- 11-001: language for text in page content cannot be determined.
- 11-002: language for text in Alt, ActualText, and E attributes cannot be determined. Alternative text written in another language than the document needs its own Lang.
- 11-003: language in the Outline entries (bookmarks) cannot be determined.
- 11-004: language in the Contents entry for annotations cannot be determined.
- 11-005: language in the TU entry (tooltip) for form fields cannot be determined.
In most documents the document-level Lang satisfies all five, because it is inherited. The conditions bite when the document language is missing, or when bookmarks, tooltips, or alternative text are written in a different language from the page.
Bilingual and multilingual documents
Bilingual publishing is routine in Canada, Belgium, Switzerland, and much of the public sector elsewhere, and the usual layouts are side-by-side columns or two sequential halves. The accessible pattern is the same for both: declare the primary language on the document, put each language's content in its own structure element with the appropriate Lang, and make sure the reading order does not interleave the two columns line by line. A screen reader then reads the whole English section in an English voice and the whole French section in a French voice. Alternative text, bookmarks, and form tooltips should exist in each language's section, or carry their own Lang if they are shared.
Checking it
- The free PDF checker reports a missing document language, and the PDF tag viewer shows the structure elements that would carry passage-level languages.
- A screen reader is the real test: with NVDA or JAWS, automatic language switching must be enabled in the synthesizer settings, then read a mixed passage and listen for the voice change. See how to test a PDF with a screen reader.
- PDF/UA checkers such as PAC report the five checkpoint 11 conditions individually, which is how to find a stray alt text or tooltip in the wrong language.
Frequently asked questions
How do I set the language of a PDF?
Set the /Lang entry in the document catalog, which WCAG technique PDF16 describes. In Acrobat it is Document Properties > Advanced > Reading Options > Language, or the Primary language fix in the accessibility checker. In Word, set the proofing language before Save As PDF. In generated PDFs it usually comes from the HTML lang attribute or a metadata option.
How do I mark a passage in another language in a PDF?
Give the passage its own structure element with a Lang entry, as WCAG technique PDF19 describes. In Acrobat, select the text, use Create Tag From Selection, then set the language in the tag's properties. This satisfies success criterion 3.1.2 and lets screen readers switch voices for the passage.
Does alternative text need its own language?
Only when it differs from the document language. PDF/UA-1 condition 11-002 fails a file where the language of Alt, ActualText, or E attributes cannot be determined; normally the document-level language is inherited. If an English document carries French alt text, put a Lang on the figure element.
Sources
The statements above rest on the primary sources below. Where a source is a law or standard, the version and date named in the text are the ones checked on the review date. This guide is general information, not legal advice.
- W3C WAI: PDF16, setting the default language using the /Lang entry in the document catalog
- W3C WAI: PDF19, specifying the language for a passage or phrase with the Lang entry . The Acrobat procedure and the ISO 639 code note.
- PDF Association: Matterhorn Protocol 1.1 (PDF) . Checkpoint 11 failure conditions 11-001 to 11-005.
- Adobe: Create and verify PDF accessibility (Acrobat Pro) . The Primary language rule and its fix.
- ETSI EN 301 549 V3.2.1 (2021-03), clause 10.3.1 Readable
Keep reading
The 5 document-level PDF settings checkers flag
The document-level PDF settings that fail accessibility checks most often: title and DisplayDocTitle, language, bookmarks, tab order, and the permission that lets screen readers read text. Where each lives and which rule tests it.
Read the guide →The Matterhorn Protocol explained
What the Matterhorn Protocol is, how its 31 checkpoints and 136 failure conditions test PDF/UA-1, which ones a machine can decide, and how to read a checker report built on it.
Read the guide →Canada document accessibility: ACA regulations and AODA
Canada's amended Accessible Canada Regulations set December 2027 and 2028 dates for web pages, apps, and non-web documents against CAN/ASC-EN 301 549:2024. Who is covered, the exemptions, and how Ontario's AODA (WCAG 2.0 AA) applies to documents.
Read the guide →