Cover image for Accessibility for the web - how do screen readers work?

Accessibility for the web - how do screen readers work?

ari_o profile image Arika O Updated on ・2 min read

People with disabilities/ special needs browse the internet differently from the rest. They can't get their information by looking at their screens so they must use tools called assistive technologies (head pointers, screen readers, touchscreens etc).

What is a screen reader and how does it work?

In simple terms, a screen reader is a software that helps people with no or limited vision to get information in a way accessible to them. It works closely with the computer's operating system (OS) and provides information about icons, dialog boxes, menus, files and folders (it translates what it sees on the screen). It provides access to the entire OS and many of the applications found on the computer.

Usually, a screen reader will start reading at the top of a page and will read any text (including alternate text for images). Some screen readers allow the user to preview information, like the navigation bar or all the headings on a page, and skip to the desired section of the page. Users do most of the navigation using the keyboard since it's more precise than a mouse.

How does a screen reader give feedback to the user?

There are two ways the screen reader translates the information: using sound (synthetic speech) or using Braille notation.

Screen readers use Text-to-speech(TTS) engines to translate the information on the screen into speech, which can be heard through speakers or headphones. A TTS can come bundled with the screen reader or it can be a hardware device that gets plugged into the computer.

For Braille output, an external hardware device called a refreshable Braille display is used (we can use it on its own but usually it's used in conjunction with speech output). The way it works is that the display contains one or more rows of cells. Each cell can be formed into the shape of a Braille character. As the information on the computer screen changes, so does the Braille characters on the display change, providing refreshable information directly from the computer.

If you're unfamiliar with web accessibility, I think the best way to understand how screen readers work by watching them in action, so I linked a video which explains just that. To watch it, click here.

Image source: Sigmund/ @sigmund on Unsplash


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