Screen readers
[Narrator:] Users with visual disabilities cannot see content on the screen. Therefore, we need an alternative solution that reads text and image descriptions to the user. This solution is called a screen reader.
A screen reader is a form of assistive technology. It is a software application that converts screen content into an audible form using text-to-speech technology. Is typically used by people with visual disabilities or impairments that make it difficult to use personal computers or handheld devices. Often supports a wide variety of Braille displays, which enable the user to read single characters of text with their fingertips.
Screen readers are available commercially or free of charge. Free screen readers are available for all major operating systems. As this course does not want to promote a single commercial product, we will only demonstrate screen readers that come bundled with the operating system or are available for free.
For our course, we will use the following screen readers. For Microsoft Windows, we will use the built-in Narrator and the free and open-source solution, NonVisual Desktop Access, NVDA for short. For Apple’s macOS, we will use the built-in VoiceOver screen reader. Apple’s iOS offers the VoiceOver screen reader as part of its operating system. Google’s Android has the TalkBack screen reader built in.
Please note, even though we only describe solutions for personal computers and hand-held devices here, screen readers are available for many other types of devices, such as: Smart watches; E-book readers; Televisions; Kitchen equipment.
Screen readers for desktop computers
As screen readers are aimed at people with visual disabilities, it is clear that the mouse cannot be used as an input device. A mouse is a pointing device that invokes different actions depending on the position of the mouse pointer on the screen, a position which cannot be perceived by people with certain visual disabilities.
A screen reader is operated by keyboard commands only. If you want to learn how to use a screen reader, you have to get used to keyboard-based commands. Even though screen readers offer hundreds of keyboard commands, it is often sufficient to learn a dozen key combinations to successfully test a PDF, web page or app.
Screen readers for mobile devices
A touch interface uses the type of gesture and its position on the screen to determine the intended operation. However, people with certain visual disabilities cannot execute a gesture at a specific screen position.
Therefore, screen readers redefine the gestures to position independent operations. Additionally, the same gesture may have a different meaning when executed in a different mode. This can be confusing for a seeing user. Even though screen readers offer many different gestures in multiple modes, it is often sufficient to learn a dozen gesture commands to successfully test a PDF, web page or app for accessibility.
Screen readers
There is no standard to define: the functionalities a screen reader offer; the keyboard or gesture commands which trigger a specific kind of action.
The VoiceOver screen reader on macOS uses different keyboard commands to NVDA running on Windows. A gesture executed on Android may have a totally different meaning when executed on an iOS device. Commercial screen readers often offer more features. For example, a screen reader may offer an optical character recognition function to convert text in images into editable text. It may offer improved support for applications programmed in Java. Often screen readers offer application-specific enhancements, such as improved support for Microsoft Office.
Other solutions offer the screen reader as part of a larger accessibility-program suite that includes a screen magnifier or a colour converter.
So, what can we learn from this? Here are two key points. First, do not rely on a specific feature of one screen reader. If a specific function of a website works with one screen reader, it does not mean that it works with others as well. Second, test your PDF, web page or app with a free screen reader. If it works, the probability is very high that it will work with a commercial screen reader as well.
Languages and voices
Screen readers can provide speech output using different languages. Each language is implemented using one or more specific voices that know how to pronounce the words of a text.
Voices are available for free or commercially. You can buy commercial voices for a free screen reader and vice versa. Voices can come bundled with the screen reader or be installed separately. Some of them come pre-installed with the operating system, or they have to be downloaded via the internet, others need to be installed via third-party services.
Voices are available in different versions. For example, you can choose between a male and a female voice. Often, voices are offered in a low- and high-quality version. In general, the high-quality version of a voice requires more calculation power and storage than its low-quality equivalent.
Text is important
All screen readers have one thing in common. They require text that can be read. It is essential that the information on the screen either is in a text form or can be converted into a text form, for example by offering alternative text descriptions.
Let’s assume we have a graphic of a heart on screen, which we want to communicate to users with visual disabilities. Technically speaking, the graphic of the heart could be implemented by an image file stored in JPEG format.
When the screen reader reaches the image, which information could it forward to the user? In a worst-case scenario, the screen reader detects only the file itself, has no concept of the content of the image, and so uses the file name, which could be very confusing, for example, 'img_2456.jpg'.
When authors consider accessibility during the creation process of their documents, they add alternative descriptions to the images. The screen reader will evaluate the alternative text and read, for example, 'Symbol of a red heart'.
Desktop screen reader usage
When we talk about screen readers, it is useful to know which screen readers are commonly used. WebAim regularly conducts screen reader user surveys. You can find a link to the complete result of these surveys below the video.
One of the questions people have been asked is what screen readers they commonly use. As you can see in the graphic, the free NVDA screen reader is the most popular screen reader.
The second most popular is the commercial Job Access With Speech, or Jaws for short, screen reader. Jaws is a product of Freedom Scientific. It is the most powerful and the most expensive screen reader on the market. It is not surprising that the Windows screen readers, Jaws and NVDA, are used by far more people than VoiceOver on macOS because the market share of Windows is much higher than that of macOS.
All other screen readers occupy only a market niche, which makes them negligible for our tests.
Our advice: if you want to test your PDF or website for accessibility with a screen reader on a personal computer with a free available solution, then use NVDA with Windows or VoiceOver with macOS.
Mobile screen reader usage
The scenario looks different when we look at the mobile use of screen readers. As Apple is very successful in the accessibility domain by enhancing all of their products with assistive technology, their mobile products are very popular for users with visual impairments or visual disabilities. The majority of this target group uses an iOS-based device. Products not based on iOS or Android are not included in our tests.
Our advice: if you want to test your PDF, website or app for accessibility with a screen reader on a mobile device, then use TalkBack on Android or VoiceOver running on iOS.
Advice: Most screen readers offer a tutorial to introduce new users to the different keyboard commands. If a tutorial comes bundled with the screen reader, then use it. The tutorial enables you to learn the most common keyboard commands first.
Screen readers are typically activated when booting the operating system, but like any other program, they can be started or stopped. If you just want to test your document for accessibility, then you can start and stop the screen reader at any time.
Be patient, learning how to use a graphical user interface via the keyboard takes time. Even though screen readers offer hundreds of keyboard commands, there is no need to learn them all. Most times, it will be sufficient to learn a dozen keyboard commands to test your document for accessibility.
Where to continue?
In this chapter, you have gained a basic understanding of what a screen reader is. In the following chapters, we will introduce different screen readers and how to use them.
Depending on your personal interests, you could continue with one of the following chapters:
- Screen readers – Windows
- Screen readers – macOS
- Screen readers – Android
- Screen readers – iOS
[Automated voice:] Accessibility. For more information visit: op.europa.eu/en/web/accessibility.