LibreOffice Accessibility Tools for Readability

This article provides an overview of the primary built-in features, extensions, and external validators used to identify readability and structural accessibility issues in LibreOffice documents. Ensuring documents are accessible involves verifying reading ease, clear heading structures, proper contrast, and alternative text for screen readers. Below are the key tools available to evaluate and improve the accessibility of your LibreOffice files.

1. The Built-in LibreOffice Accessibility Checker

Modern versions of LibreOffice (version 7.2 and later) include a native Accessibility Checker. This tool scans the active document against universal accessibility guidelines (such as PDF/UA and WCAG standards) and flags issues directly in a dedicated sidebar deck.

To access the tool: * Navigate to Tools > Accessibility Check from the top menu. * The sidebar will display identified issues categorized by severity (Errors, Warnings, and Information).

The built-in checker detects: * Missing alternative text for images, shapes, and OLE objects. * Ambiguous or missing heading hierarchy (e.g., skipping from Heading 1 directly to Heading 3). * Table issues, such as missing header rows, merged cells, or complex splits that confuse screen readers. * Insufficient text contrast against background colors, which impairs visual readability. * Manual formatting used instead of proper styles.

2. LanguageTool Extension

While structural accessibility is essential, text readability and cognitive accessibility are equally critical. LanguageTool is a widely used open-source grammar and style checker extension for LibreOffice.

LanguageTool identifies: * Overly complex or lengthy sentences that reduce readability. * Passive voice overuse. * Confusing word choices, typographical errors, and grammatical inconsistencies. * Plain-language violations that make content difficult to understand for diverse audiences.

3. Readability Report Extensions

Several third-party extensions compute standard readability formulas (such as the Flesch Reading Ease and Flesch-Kincaid Grade Level formulas) directly within LibreOffice Writer.

These tools analyze word length, syllable count, and sentence length to assign a readability score. This allows authors to adjust their writing level to match the target audience’s reading proficiency, ensuring cognitive accessibility.

4. AccessODF (for OpenDocument Format)

AccessODF is an extension designed to evaluate OpenDocument Text (.odt) files. It assesses the document against accessibility rules similar to the DAISY Consortium standards, flagging structural barriers such as missing language tags, unanchored objects, and non-linear reading orders.

5. Exporting to PDF/UA and External Verification

When sharing documents, exporting to an accessible PDF format is standard practice. LibreOffice includes a built-in “Universal Accessibility (PDF/UA)” export option under File > Export As > Export as PDF.

Once exported, you can use specialized external accessibility checkers to ensure full compliance: * PAC (PDF Accessibility Checker): A standard tool for validating PDF/UA compliance, reading order, and document tagging. * VeraPDF: An open-source PDF/A and PDF/UA validator.

By combining the native LibreOffice Accessibility Check with language readability extensions and PDF validation tools, you can ensure that documents are both structurally accessible to assistive technology and easy to read for all users.