# Accessibility Support - Overview

**RadPdfProcessing** provides *accessibility support* for documents to users with disabilities. This support allows users with visual impairments to use screen readers that read documents aloud. To enable proper vocalization, either through a screen reader or by some more direct invocation of a text-to-speech engine, the PDF document must support the following features:

* Specifying the natural language used for text in a PDF document
* Providing textual descriptions for images or other items that do not translate naturally into text, or replacement text for content that does translate into text but is represented in a nonstandard way
* Specifying the expansion of abbreviations or acronyms

The core of this support lies in the ability to determine the logical order of content in a PDF document, independently of the content appearance or layout, through [logical structure](https://www.telerik.com/document-processing-libraries/documentation/libraries/radpdfprocessing/model/structure-tree) and [Tagged PDF](https://www.telerik.com/document-processing-libraries/documentation/libraries/radpdfprocessing/model/tagged-pdf).

## See Also

* [RadPdfProcessing](https://www.telerik.com/document-processing-libraries/documentation/libraries/radpdfprocessing/overview)
* [Tagged PDF](https://www.telerik.com/document-processing-libraries/documentation/libraries/radpdfprocessing/model/tagged-pdf)
* [Marked Content](https://www.telerik.com/document-processing-libraries/documentation/libraries/radpdfprocessing/model/marked-content)
* [StructureTree](https://www.telerik.com/document-processing-libraries/documentation/libraries/radpdfprocessing/model/structure-tree)
* [PdfProcessing Accessibility Demo](https://demos.telerik.com/document-processing/pdfprocessing/accessibility)