PDF Language Setter
Set or change the document language metadata in any PDF. The pdf language setter reads the current /Lang entry, lets you choose from 50+ BCP 47 language tags or enter a custom one, and downloads the updated PDF instantly - all in your browser, with no file upload required.
Why Use Our PDF Language Setter?
Instant Language Tagging
Upload a PDF, choose your BCP 47 language tag, and download the updated file in seconds - no software installation, no waiting, and no size limits on your documents.
50+ Languages Supported
The pdf language setter includes a pre-built list of over 50 common language tags - from en-US and fr-FR to zh-CN and ar - or enter any valid custom BCP 47 subtag for full flexibility.
Completely Private - Runs in Your Browser
All processing runs locally in your browser using pdf-lib. Your PDF never leaves your device, so confidential documents and personal files stay completely secure.
Reads the Existing Language Before You Edit
The tool displays the current /Lang metadata value as soon as you upload your PDF, so you can verify the existing language tag and make an informed, accurate change.
Common Use Cases for PDF Language Setter
PDF/UA & WCAG Compliance
A correctly set /Lang entry is a hard requirement for PDF/UA (ISO 14289) and a WCAG 2.1 Success Criterion 3.1.1 requirement. Use the pdf language setter to tag every document before submitting for accessibility audit.
Screen Reader Pronunciation
Screen readers like NVDA, JAWS, and VoiceOver use the PDF /Lang value to select the correct text-to-speech engine and pronunciation rules. Setting the right language ensures your document is read aloud correctly.
Multilingual Document Publishing
If your publishing pipeline produces PDFs without the correct /Lang metadata, use the pdf language setter as a post-processing step to correct language tags before distribution.
Government & Public Sector Filing
Many government portals and procurement systems require PDFs that meet Section 508 or EN 301 549 accessibility standards, which mandate a declared document language - use this tool to add or fix the tag instantly.
Fixing Exported PDFs
PDFs exported from legacy systems, print workflows, or non-accessible templates often lack a /Lang entry. The pdf language setter lets you correct this without going back to the source document.
SEO & Search Indexing
Search crawlers, including Google, use the declared language to index and serve your PDF content to the correct regional audience. Setting the language tag helps ensure your PDF ranks for the right locale.
Understanding PDF Document Language
What is the PDF /Lang Metadata Entry?
Every PDF document can carry a /Langentry in its catalog dictionary - a metadata field that declares the natural language of the document's content using a BCP 47 language tag (e.g. en-US, fr-FR, zh-CN). This tag tells screen readers, search engines, and assistive technology which language to use when processing the document. Without a /Lang entry, screen readers fall back to the operating system language, which frequently causes incorrect pronunciation and breaks reflow for right-to-left scripts like Arabic and Hebrew. The pdf language setter writes this tag directly into the PDF catalog without altering any page content or visual layout.
How Our PDF Language Setter Works
- Upload: Drop your PDF into the tool. The pdf language setter reads the existing /Lang entry from the PDF catalog using pdf-lib, running entirely in your browser - no upload to any server.
- Select:Choose from the 50+ common BCP 47 language tags in the dropdown, or select “Enter a custom BCP 47 tag” and type any valid subtag sequence (e.g.
pt-BR,zh-Hant-TW,sr-Latn). - Apply & Download:Click “Apply & Download PDF”. The tool writes the new /Lang value into the catalog dictionary and triggers an immediate browser download of the updated PDF.
BCP 47 Language Tag Structure
- Primary language subtag (required): Two or three-letter ISO 639 code identifying the language - e.g.
en,fr,zh. - Region subtag (optional): ISO 3166-1 country code after a hyphen, specifying the dialect or regional variant - e.g.
en-US,fr-CA,pt-BR. - Script subtag (optional): ISO 15924 four-letter script code placed before the region - e.g.
zh-Hant-TW(Traditional Chinese, Taiwan),sr-Latn(Serbian, Latin script). - Variant subtags (advanced): Additional subtags can specify orthographic variants, extensions, or private-use ranges for highly specific linguistic requirements.
Privacy, Security & Limitations
The pdf language setter runs entirely client-side - your PDF is never transmitted to any external server, making it safe for confidential, medical, or legal documents. The tool modifies only the /Lang entry in the catalog dictionary; all page content, images, fonts, annotations, and form fields remain completely unchanged. Note that this tool sets the document-level language only; individual tagged structure elements can carry their own /Lang attribute, which requires a full PDF accessibility remediation workflow to set.
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Frequently Asked Questions About PDF Language Setter
The /Lang entry in a PDF catalog dictionary declares the natural language of the document using a BCP 47 tag (e.g. en-US, fr-FR). Screen readers use this to select the correct text-to-speech engine. Without it, assistive technology falls back to the OS language, which causes mispronunciation and broken reading order for non-English or right-to-left content. It is also a hard requirement for PDF/UA and WCAG 2.1 compliance.
BCP 47 is an IETF standard for language identification. A tag consists of subtags separated by hyphens: a two-letter primary language code (e.g. en, fr), an optional four-letter script code (e.g. Hant), and an optional two-letter region code (e.g. US, GB). Examples: en, en-US, zh-CN, zh-Hant-TW, pt-BR, sr-Latn.
No. The pdf language setter only modifies the /Lang metadata entry in the PDF catalog dictionary. All page content, fonts, images, annotations, and form fields remain completely unchanged. The visual output of the PDF is identical to the original.
It depends on the use case. For accessibility compliance (PDF/UA, WCAG 2.1 SC 3.1.1, Section 508), a missing /Lang entry is a failure that must be corrected. For general distribution it may not be an issue, but adding a language tag is always recommended for documents with text content.
No. The pdf language setter runs entirely in your browser using the pdf-lib JavaScript library. Your file is read locally and never transmitted to any external server, making it completely safe for sensitive or confidential documents.
No - this tool sets the document-level /Lang entry only. Individual tagged structure elements (e.g. a span of French text inside an English document) can carry their own /Lang attribute, but setting those requires a full PDF accessibility remediation workflow in a tool like Adobe Acrobat Pro.
Yes, completely free. There is no registration required, no file size limit, and no restrictions on how many PDFs you process.
Yes. Select "Enter a custom BCP 47 tag…" from the dropdown and type any valid BCP 47 subtag sequence. The tool validates the format before applying it to ensure you do not write a malformed /Lang value into the PDF.