Testing publications with NVDA – Configuration
Introduction
[Narrator:] NonVisual Desktop Access (NVDA) is a free and open-source screen reader for Microsoft Windows. NVDA is developed by NV Access and can be downloaded from their website www.nvaccess.org. This chapter is intended to offer an introduction on how to install, configure and use the NVDA screen reader to test documents for accessibility.
Even though screen readers primarily address visually disabled users, this course does not. This course addresses content authors who want to use the screen reader to test their documents for accessibility.
We can use different tools and technologies to test the accessibility of documents or publications, such as if they have:
- Error-free code.
- Meta-information.
- Alternative descriptions for images.
- A consistent structure for heading levels, tables and lists.
For more information about how to use these tools, please refer to the chapters Testing PDFs, HTML testing or EPUB testing. Please use these tools and methods to fix the most important accessibility problems before testing with a screen reader. Once a document has passed these tests, a screen reader can be used to check additional problems.
Why should you test a document with a screen reader?
A screen reader can give you the possibility to experience your document as a visually disabled user would. Here are some issues that testing with screen readers can help to detect:
- Whether the document can be navigated easily.
- Whether all parts of your document are reachable.
- Whether the content is presented in the correct sequence.
- Whether the semantics fit the purpose of each element.
- Whether the language of the content has been correctly specified.
We will see some examples in the following chapters.
Installing NVDA
This is the homepage of NV Access. To download NVDA follow the Download link. You can see a detailed process of the installation in the chapter Screen readers – Windows.
Although throughout this process a sighted user may as well use the mouse, we will also show, below the NVDA screen, the keys or combinations of keys that we would need to navigate through the screens from the keyboard only.
[Screen reader:] Welcome to NVDA dialogue Welcome to NVDA! Desktop.
[Narrator:] Once it has been installed, the first time it starts, a dialogue box will open, which provides you with some basic information about the keyboard layout, the NVDA modifier key and the NVDA menu.
[Screen reader:] Expanded.
[Narrator:] The combo box lets you select the keyboard layout.
Keyboard layouts
NVDA comes with two sets of key commands, known as keyboard layouts: the desktop layout and the laptop layout. By default, NVDA is set to use the desktop layout. The desktop layout makes heavy use of the numeric keypad.
If your laptop does not offer a numeric keypad or does not allow you to turn Num Lock off, you may want to switch to the laptop layout instead.
Our advice is always to use the desktop keyboard layout for the following reasons:
- You do not have to learn a different set of keyboard commands if you switch between a laptop and a desktop machine.
- Even though some laptops do not have a physical numeric keypad, they can emulate one by pressing various other key combinations.
- If you use NVDA more often with a laptop, you can get yourself an external numeric keypad.
[Screen reader:] Collapsed. Use CapsLock as an NVDA modifier key checkbox not checked.
[Narrator:] The first checkbox lets you control whether NVDA should use the Caps Lock as an NVDA modifier key. The second checkbox specifies whether NVDA should start automatically after you log in to Windows and is only available for installed copies of NVDA. The third lets you control whether this welcome dialogue should appear each time NVDA starts. Let’s talk about the NVDA modifier key.
The NVDA modifier key
In NVDA, most keyboard commands consist of pressing what is called the modifier key in combination with other keys. By default, this modifier key is the Insert key on both the main keyboard and the number pad. Moreover, when the Num Lock is turned off, the 0 key at the bottom of the number pad will also function as an Insert key.
On top of that, you can also select the Caps Lock key to be used as the modifier key. This has the advantage that this key is usually used with the left hand, and therefore it does not interfere with combinations using other keys. In any case, if you don’t select this in this first menu, you will be able to do it later on from the Settings panel.
Finally, if you want to make one of the NVDA modifier keys behave as it usually would if NVDA were not running, for example if you wish to turn Caps Lock on when you have set Caps Lock to be the NVDA modifier key, you can press the key twice in quick succession.
Once it has started, NVDA immediately reads text to the user. Even though this is the core function of a screen reader, this may confuse sighted beginners. We can therefore silence the speech output using the NVDA modifier and the S key.
[Screen reader:] Speech mode off.
The NVDA menu
[Narrator:] Other options can be configured using the NVDA menu. To get to the NVDA menu from anywhere in Windows, press the NVDA modifier key and the N key on the keyboard. You can now navigate the menu using the arrow keys. Use the Tab key to switch between interactive controls and the space bar to activate or deactivate a checkbox.
Since the purpose of this video is not to review NVDA in detail, but just to demonstrate how to use it to test different types of documents, we will only be covering the settings that we need for this purpose.
By the way, we are describing the configuration of NVDA. During the configuration phase a sighted user may want to use the mouse. For real document testing, please use the keyboard only.
Let’s have a look at Preferences, Settings.
The Speech category contains options that let you change the speech synthesiser and the voice characteristics for the chosen synthesiser. The first option allows us to select a synthesiser. For Windows 10, NVDA uses Windows OneCore voices as default. For older Windows releases, eSpeak NG is the preferred option. As the eSpeak synthesiser is built into NVDA, this is a great choice when running NVDA from an external drive on other systems. Each voice that comes with eSpeak speaks a different language or dialect. More than 80 different languages are supported by eSpeak. The eSpeak NG voices are a good solution for testing whether languages are switching in your test document. As they are already bundled as part of NVDA, there is no need to install them separately.
Microsoft Speech API version 5 is a Microsoft standard for software speech synthesisers. Many speech synthesisers that comply with this standard can be purchased or downloaded for free from various companies and websites.
You will notice that different speech synthesisers offer different options. Here are the ones that come with Windows OneCore voices. If there is an error loading the synthesiser, NVDA will notify you with a message, and will continue using the previous synthesiser.
Unless there is a specific reason to do so, for example you are working in a language that is not offered by the Windows OneCore voices, we recommend that you do not change the default synthesiser. Using this one we can choose between different voices, and we can adapt the speech rate, pitch and volume.
The next option is important when we operate and handle documents in different languages. Make sure you activate Automatic language switching and Automatic dialect switching so documents or parts of documents are spoken using the correct language.
The Punctuation/symbol level pop-up allows you to choose the amount of punctuation and other symbols that should be spoken as words. For example, when you select the value “all”, all symbols will be spoken as words.
The Say cap before capitals checkbox instructs NVDA to say the word “cap” before any capital letter when spoken as an individual character, such as when spelling.
If the checkbox Beep for capitals is checked, NVDA will make a small beep noise each time it encounters a capitalised character by itself.
If we want to install more languages in Windows, we need to stop NVDA. To stop it, press the NVDA modifier key and Q.
Installing more languages in Windows
NVDA can enable the user to read content in any language, as long as they have a speech synthesiser that can speak that language.
To install additional languages in Windows 10, click on Settings, Time & Language, and Speech. Scroll down to Manage voices. Below you can see a list of the voices already installed. Click Add voices. A dialogue box will open in which you can select one or more additional voices. Search for the desired language. Many languages include multiple variants. For example, Australia and Canada are two of the English variants, while Canada, France and Switzerland are available French variants. Search for the broader language, such as English or French, and then locate the variant in the list. Select any desired languages and use the Add button to load them.
Please note that the new voices need to be downloaded from the Internet. Depending on the number of voices you select and the speed of your internet connection, it may take some time to download the data.
Once the voices have been downloaded, restart NVDA.
[Screen reader:] Speech mode off.
[Narrator:] Let’s click again in Preferences and Settings to continue our configuration.
The Vision category allows you to enable, disable and configure visual aids. While NVDA is primarily aimed at blind or vision-impaired people who primarily use speech and/or braille to operate a computer, it also provides built-in facilities to change the contents of the screen. As this course addresses visually enabled users who want to test their documents for accessibility, these configurations are very useful.
Visual Highlight can help to identify the system focus, navigator object and browse mode positions. These positions are highlighted by outlining with a coloured rectangle. We will see these highlights in action while testing the documents. For the moment just keep in mind that these highlights help you to identify the position of the screen reader cursor and the type of operation.
When Visual Highlight is enabled, you can choose whether or not to highlight the focus, the navigator object and the browse mode caret. We will explain this in detail later on, but for the moment let’s enable all these options.
The Keyboard category contains options that set how NVDA behaves as you use and type on your keyboard. Here you can change the keyboard layout and the NVDA modifier key selection, which you have set through the Startup dialogue box.
The Document Formatting dialogue offers a set of checkboxes for configuring what type of formatting you want to have reported as you move the cursor around documents. For example, if you check the Font name checkbox, each time you read text with a different font, the name of the font will be announced. We have no interest in font-styling information, but we would like all HTML and PDF content elements to be announced, therefore we will activate all the elements.
Let’s talk now about the Tools menu in the NVDA menu.
The Speech viewer shows a floating window that allows sighted users to view all the text that NVDA is currently speaking. This option is also very useful for people who have difficulties understanding the computer-generated voice.
It is also useful for checking information previously spoken. Moreover, the speech viewer also allows you to use the screen reader without an audio output when you cannot or do not want to listen to the speech output.
The Help menu offers you direct access to the User Guide, Commands Quick Reference, Release notes, the web site and much more.
Navigation basics valid for all application scenarios
Even though NVDA offers some application- and mode-dependant keyboard commands, some of them are always the same. Here are the most important ones to get you started. To keep things simple, we will say Insert key to refer to the modifier key, but remember that it can also be the Caps Lock key.
- Press the Control, Alt and N keys to start or restart NVDA. This is a Windows shortcut, which is enabled during NVDA’s installation process.
- Press the Insert key and Q to quit NVDA.
- Press the Insert key and S to mute the sound when not needed. This toggles the speech mode off, speech mode beeps and speech mode talk.
- Press the Insert key and the Down arrow to start reading from the current position.
- Press the Insert key and the Up arrow to start reading the current line.
- Press the Control key to pause/restart the reading.
- Press the Shift key to pause or continue speech where it left off.
- Press the Tab key or Shift Tab to reach the next or previous focusable element, such as a link or an input field.
- Press the Insert key and F7 to open the elements list dialogue to check the document links, headings, form fields and landmarks.
- Press the Down arrow to read the next item.
- Press Control and the Down arrow to read the next paragraph.
- Press the Control, Alt and Arrow keys to navigate inside a table.
- Press Enter to activate a link or a button.
- Press Space bar to activate a button and interact with the selected checkbox.
As previously mentioned, the desktop keyboard layout makes use of the numeric keypad. The numbers on the numeric keypad can be used for text navigation.
- Press 9 or 7 for the next or previous line.
- Press 6 or 4 for the next or previous word.
- Press 3 or 1 for the next or previous character.
Please remember: keys on the numeric keypad require the Num Lock to be turned off to work properly.
Navigation modes
NVDA offers different ways of interacting with the underlying application. The most common ones are the browse mode and the focus mode.
To read the elements in a document, NVDA follows the sequence in the Tags panel of a PDF or in the DOM tree of an HTML page. Reading a document by navigating from element to element is called browse mode. In this mode, the user can read the content line by line using the Down arrow, or the Up arrow to go back. Moreover, in this mode, the screen reader cursor can be placed on different elements:
- Press D or Shift D to go to the next or previous landmark. Landmarks are special regions in a web page that assistive technologies can use to support users in navigating the document. Examples of landmarks are header, footer, navigation or main.
- Press H or Shift H to go to the next or previous heading. Press the numbers from 1 to 6 to go to specific levels.
- Press G or Shift G to go to the next or previous graphic.
- Press T or Shift T to go to the next or previous table.
- Press L or Shift L to go to the next or previous list.
- Press K or Shift K to go to the next or previous link.
- Press F or Shift F to go to the next or previous form field.
We will demonstrate the use of all these shortcuts in the next chapters. Moreover, from our platform you can also download a list that shows all of them, which would be useful to keep in front of you when testing the documents.
While the browse mode allows you to read elements, it does not allow you to interact with them, for example to enter text in a field or choose a value from a combobox. Imagine that, using the browse mode, you are reading a website or a PDF that has input fields. If you were to enter an input field and type H, the screen reader would move its cursor to the next heading. If this is not what you wanted to do, you would need to tell the screen reader not to intercept your keystrokes anymore.
The mode in which keystrokes aren’t intercepted, but are instead sent directly to the controlled application, is called focus mode. When the screen reader’s cursor is on an editable element, it allows you to switch to focus mode using the Enter key. A high-pitched beep announces the change to focus mode. You can leave focus mode by pressing Escape. A lower-pitched beep indicates a change back to browse mode. Press the Insert key and the Space bar to toggle between the browse and focus modes.
For elements that allow only basic interaction, for example links, buttons and checkboxes, focus mode cannot be activated.
System focus, System caret and Review cursor
Previously we have mentioned these terms while configuring the Visual Highlight. Now we have the background knowledge to understand what they are.
System focus
Also known simply as the focus, this is the object that receives keys typed on the keyboard. For example, if you are typing into an editable text field, the editable text field has the focus. The most common way of navigating around with NVDA is to simply move the system focus using standard Windows keyboard commands, such as pressing Tab and Shift Tab to move forward and back between controls.
System caret
When an object that allows navigation and/or editing of text is focused, you can move through the text using the system caret, also known as the edit cursor.
When the focus is on an object that has the system caret, you can use the arrow keys, page up, page down, home, end, etc., to move through the text. You can also change the text if the control supports editing. As you move by characters, words and lines, and as you select and unselect text, NVDA will announce it.
Review cursor
Often only called the cursor, it allows you to read the contents of the screen, current document or current navigator object by character, word or line. When moving the review cursor, the system caret does not follow along, so you can review text without losing your editing position. However, by default, when the system caret moves, the review cursor follows along. This can be toggled on and off in the configuration menus.
Where to continue?
You have now had a general introduction to the NVDA screen reader on Windows. We will use this knowledge in the following chapters to demonstrate how to test your documents for accessibility.
Depending on your personal interests, you could continue with one of the following chapters:
- Testing publications with NVDA: Web pages.
- Testing publications with NVDA: PDFs.
- Testing publications with NVDA: EPUBs.
[Automated voice:] Accessibility. For more information visit: op.europa.eu/en/web/accessibility.