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Assistive technology macOS

[Narrator:] In this chapter we will discuss the accessibility features that come bundled with the macOS operating system. For our course, we will use macOS 10.15, also called macOS Catalina. Please note that Apple updates and changes its operating system from time to time. So, your screen or set of functionalities might look slightly different from the ones described in this tutorial.

Apple is very successful in the accessibility domain and there are good reasons for this. The accessibility functions are part of every operating system without extra charge. All their devices come bundled with assistive technology. The macOS personal computer as well as the iPhone, iPad, iPod Touch, Apple Watch and Apple TV use similar accessibility features which creates a cross-device user experience.

MacOS offers a variety of accessibility tools to customize the computer. So it is easier to use. Users with different kinds of disabilities will find potential solutions. To access the accessibility tools, open System Preferences and click Accessibility. The Accessibility control panel offers supporting functions for problems with vision, hearing and physical interaction. In the following sections we will introduce and demonstrate these tools and functions.


Zoom is a screen magnifier. It is primarily designed for people with limited vision capabilities, but it can be useful for anyone who needs to focus on a small part of the screen.

You can activate or deactivate the screen magnification using keyboard shortcuts or a scrolling gesture initiated by the scroll wheel of a mouse or via the touch pad. I am using the scroll wheel of my mouse.

The zoom function is activated when scrolling more, pressing the defined modifier key. A rectangular area centred by the pointer is enlarged and we can see details more clearly. The more we scroll, the more the zoom factor increases.

When we scroll back, the zoom factor decreases. The control panel offers additional options. We can activate keyboard shortcuts to zoom the screen. We can configure a different modifier key to be used together with the scroll gesture. If we do not like the picture-in-picture style of the zoom presentation, we can change it to full screen. Another option offers a split screen view. You can display a large-text view of the item under the pointer.

The Advanced parameters allow many more parameters of the zoom function to be configured. We will look at two possible configuration options. The first inverts the colours in the zoom

area, which can help if you have problems seeing colours. The second function offers you the possibility to adjust the size and location of the area to be zoomed.

Feel free to experiment with the other options if they can enhance your user experience.

One remark: If you do not like the zoom function, but you prefer that all the elements of your screen appear bigger, then you can use the Display control panel to adjust the resolution of your screen. The lower the resolution, the bigger the items will appear on your screen.


The Display panel in the Accessibility control panel offers functions to adjust display options.

We can invert the colours on the screen for those who need it.

Reducing motion makes animations more subtle. For instance, when you arrange windows on multiple virtual screens, the animation of the windows is replaced by a crossfade. Increasing contrast on your Mac can help text stand out more clearly and can also help buttons and app icons appear more pronounced.

Reducing transparency helps your dock and desktop icons stand out more and also makes the top menu bar opaque so that you can clearly see all your app icons and menu items. This is especially useful if you are using photos as background images.

The Differentiate without colour option instructs applications to use shapes, in addition to or instead of colour, to convey status or information. However, we have not found any practical example to demonstrate this to you.

If you like, you can change the contrast of the display. If you are a designer and you want to make sure that your document, website or app is accessible to users with colour deficiencies, check that all the content is distinguishable without colour.

To deactivate colours, select Colour Filters and select the filter type Greyscale. Now test your document. Can all the elements be identified? Is all the text legible? Is the difference in brightness large enough? So the different elements offer enough contrast.

The Filter type pop-up offers more options to support people with colour deficiencies. You can increase or decrease the size of the mouse pointer, which is not only useful for people with visual impairments. This can be useful for many users, especially those working with larger high-resolution monitors. To help them find the position of their mouse pointer. If you cannot find the position of your mouse pointer on screen, you can activate a feature that will increase the mouse pointer size when shaking the mouse.


VoiceOver is the built-in screen reader. A screen reader is essentially software, that reads screen content to the user. Beyond pure audio output, a screen reader can make use of braille

displays to display the text in a tactile form. This allows a user with visual disabilities to read text character by character.

To start or stop VoiceOver, toggle the checkbox Enable VoiceOver.

[Screen reader:] Welcome to VoiceOver. VoiceOver speaks description of items on the screen and can be used to control the computer using only your keyboard. If you already know how to use VoiceOver, press the V key now. If you want to learn how to use VoiceOver, press the Space Bar now.

[Narrator:] To start the VoiceOver Training, click the button Open VoiceOver Training.

[Screen reader:] The VoiceOver Quick Start. In this Quick Start, you will learn VoiceOver basics as well as important VoiceOver commands to help you navigate on your Mac and use apps. You can exit the Quick Start at any time and finish it later. To advance to the Quick Start panels now...

[Narrator:] To configure VoiceOver, click the button Open VoiceOver Utility. The VoiceOver Utility allows you to configure many different options. In the Screen readers - macOS chapter, we will take a closer look at all these features. A few things are worth mentioning here.

Obviously, a screen reader needs a voice to speak with. The voice defines the pronunciation of the words and phrases to be read. Therefore, a voice is language dependent. MacOS comes bundled with a set of pre-installed voices. If you need a voice using a different language or you prefer to install a high-quality version of a voice, select Speech and then the Voices tab. Select or add the languages you need. If your language is not shown in the default section, add it by clicking the plus icon. Select the language you want to add. The system will select one or more default voices, that come bundled with the selected language. If you want a different voice, open the voice pop-up and select your voice. More voices are available via the Customize option.

You will see Compact voices and high-quality voices. Compact voices are smaller in file size. So they load faster, but offer a lower speech quality.

[Voice sample in a foreign language.]

[Voice sample in a foreign language.]

[Voice sample in a foreign language.]

[Voice sample in a foreign language.]

[Narrator:] Once you confirm your selection, macOS will start downloading the voice. Please note that, depending on the file size, it might take a few minutes before the voice is available.

For more information about the VoiceOver screen reader and how to configure it, please refer to the Screen readers - macOS chapter.


In the previous section we saw how to install voices in the VoiceOver control panel. These voices can also be used in other speaking functions of the operating system. MacOS allows us to read any text using standard functions of the operating system.

To set the voice macOS should use to read the text, select the Speech pane in the Accessibility control panel. Select the voice of your choice in the pop-up. Press the play button to listen to a short sample of the voice.

[Screen reader:] Most people recognize me by my voice.

[Voice sample in a foreign language.]

Voice sample: Hello! My name is Daniel. I'm a British English voice.

[Narrator:] Use the slider to adjust the speaking rate.

Voice sample: Hello! My name is Daniel. I'm a British English voice.

Voice sample: Hello! My name is Daniel. I'm a British English Voice.

[Narrator:] Let's try it in another application. For our example, we open TextEdit, but this can be done in many other programs, for example Safari or Pages. Select a text, open the Context-sensitive menu with a right mouse-click and select Speech, Start speaking.

[Screen reader:] Approximately 80 million Europeans have 1 or more disabilities ranging from colour-blindness to a motoric handicap, which hinders or limits their use of the web. With the European population ageing, this number is expected to…

[Narrator:] Choose a voice that fits the language of your text as otherwise you might hear some very strange pronunciation.

[Screen reader in French reading a text in English.]

[Narrator:] In many programs, the Start speaking option is missing from the Context-sensitive menu. In which case, it might be useful to activate a key combination to start speaking the selected text. To demonstrate we use the Firefox web browser. We select a text and press the previously defined key combination. The text is spoken.

[Screen reader:] Accessibility of websites and mobile apps. A study on the current practices regarding accessibility statements, reporting mechanisms and mobile monitoring methodologies.

[Narrator:] By pressing the same key combination again, we can stop the reading process.


You can use the Dictation function of your Mac to convert spoken words into text. The dictation function is simply a keyboard alternative. Therefore, you can find it in System Preferences in the Keyboard control panel. Once you are in the Keyboard control panel, select the Dictation tab. Activate the dictation function by pressing the On radio button.

The first time you select this, a dialogue box will open, which says 'When you dictate text, what you say is sent to Apple to be converted to text.'. If this raises privacy issues for you, then you might want to reconsider using the dictation function. For more information, press the About Dictation & Privacy button.

If you want to dictate in multiple languages, you might want to select another language. Next decide which keyboard shortcut to use to activate the dictation function. By default, it is pressing the function key twice.

If you have multiple audio input sources connected to your Mac, then use the microphone as the quality of the speech recognition is directly related to the quality of the speech recording. Speak in a calm voice that is not too quiet or too loud. Avoid background noise. If you use dictation in a noisy environment or a room with excessive echo, it may help to use a headset microphone. Let's try it. We start a word processor, for example, Pages. Let's dictate some text. Please note that dictation does not generate any punctuation. You have to dictate all punctuation.

[User:] Approximately – numeral 80 million – Europeans have one or more disabilities. Open parenthesis – ranging from colour-blindness to a motoric handicap. Close parenthesis – which hinders or limits their use of the web. Full stop - new line. Is this text recognized correctly - question mark - smiley face.

[Narrator:] To stop dictating, click Done below the microphone icon. Press the function key once or switch to another window. You can find a list of punctuation characters on the Apple website.

Voice Control

With Voice Control you can navigate and interact with your Mac. Using only your voice instead of a traditional input device. Voice Control is available starting from macOS version 10.15, also called Catalina.

To activate Voice Control, select it in the Accessibility control panel. Select your preferred language. If you want to use a different language, select Add Language from the pop-up menu and download an additional language. Select your audio input device using the microphone pop-up selector. In our demonstration, we are using an external microphone.

The first time you enable Voice Control, the system will ask to download an additional software package. This software will enable Voice Control to work offline. To make it easier to know whether Voice Control heard your phrase as a command, you can select Play sound when command is recognized in the Voice Control preferences.

To get an overview of the available voice commands, click Commands. You can review this list at any time while Voice Control is activated by saying Show commands. The list varies based on context and you may discover variations that are not listed.

When Voice Control is enabled, you can see an on-screen microphone. To pause Voice Control and stop it from listening, say Go to sleep or click Sleep. To resume Voice Control, say or click Wake up.

Voice Control recognizes the names of many apps, labels, controls and other on-screen items. So, you can navigate by combining those names with certain commands. Let's try it.

[User:] Open Safari.

[Narrator:] When the cursor is in a document, email, text message or other text field, you can dictate continuously. Dictation converts your spoken words into text.

[User:] Letter O. Letter P. Press Return key.

[Narrator:] Use number overlays to quickly interact with parts of the screen that Voice Control recognizes as clickable, such as menus, check boxes and buttons.

[User:] Show numbers. 15. Show numbers.

[Narrator:] As you can see, there are clickable areas in the centre of the web page that cannot be reached with the number navigation. You can use grid overlays to interact with parts of the screen that do not have a control or that Voice Control does not recognize as clickable.

[User:] Hide numbers. Show grid. 14. Click 14. Show numbers. 47. Quit application.

[Narrator:] You can even create your own commands. In the Accessibility control panel, select Voice Control. Select Commands, click the plus button. Define your spoken command, select the application and the action to be performed. Let's try it.

[User:] Open Safari. My publications.


Siri is the intelligent personal assistant on your Mac. The assistant uses voice queries and a natural-language user interface to answer questions, make recommendations and perform actions by delegating requests to a set of internet services.

To ask Siri, take any of the following actions, then just say what you need. Click the Siri icon in the menu bar, dock or touch bar. If Siri is already open, click the Siri icon or the microphone icon in the Siri window. Press-and-hold the Command key and Space bar until Siri responds. Say 'Hey Siri' on a Mac that supports this. On notebook computers that support this feature, the lid must be open. You can now start to interact with your Mac using your voice.

[User:] What’s the weather in Luxembourg?

[Siri:] Here is the weather for Luxembourg today.

[User:] Search the web for images of the Eiffel Tower.

[Siri:] Here are some images of the Eiffel Tower I found on the web.

[User:] Schedule a call with Steve tomorrow at 9 am.

[Siri:] Okay, I setup your appointment with Steve for tomorrow. Ready to set. Your appointment with Steve is scheduled for tomorrow from 9 am to 10 am.

[Narrator:] As a personal assistant, Siri accesses your contacts and calendar data to support you in your actions. Furthermore, Siri can only be used when connected to the internet. If this raises some privacy issues for you, you might want to reconsider using Siri.

You can configure Siri in combination with other accessibility features in the Accessibility control panel. In case you do not want or cannot speak the text for Siri, you may prefer to type your request. This can also be useful in a meeting or in a very noisy environment.

[Siri:] Here is the forecast for Luxembourg for today.

[Narrator:] You can find more parameters in the Siri control panel. As Siri is a very common function of macOS and we want to focus on the accessibility specifics, we will not go into the details here.


The Audio pane in the Accessibility control panel allows you to set several parameters for people with auditory problems. You can choose to flash the screen as an alternative to an alert sound. You can test the effect using the button Test Screen Flash.

When the checkbox Play stereo audio as mono is activated, all stereo audio will be converted to mono. More parameters can be set using the Sound control panel.

When activating the Output tab, you can set the balance of the audio output. If your right ear can perceive only half of the loudness that your left ear can, then it is useful to play the audio signal of the right channel using twice the volume of the left channel.


The Accessibility control panel allows you to set several parameters related to Captions. Captions let you read the words spoken in the audio portion of a video.

You can customize different appearance parameters. Several predefined values are available, from which you can choose. Of course, you are free to define your own appearance parameters using your colours, sizes and fonts. Additionally, the control panel allows you to choose subtitles for the deaf and hard of hearing or captions instead of standard subtitles if available.

Standard subtitles assume the viewer can hear but cannot understand the language. So, they transcribe only dialogue and some on-screen text. Captions aim to describe all significant audio content, spoken dialogue and non-speech information. Most of the world does not distinguish captions from subtitles. In the United States, these terms have different meanings. As Apple is an American company, the control panel offers this option.

On-screen keyboard

To open the On-Screen Keyboard, start the Accessibility control panel and select Keyboard. Select the tab Accessibility Keyboard. Activate the Enable Accessibility Keyboard checkbox. The keyboard panel appears on screen.

Open a text editor, for example Pages. Now you are able to type text without using your hardware keyboard just by clicking the keys on screen with a pointing device. For example, the mouse or track pad.

To configure your panel, click the Options button. The options dialogue will open. You can define the number of seconds after which the panel should fade automatically. The slider allows you to set the level of transparency when fading. There is an option that gives sound feedback when keys are pressed. You can start a typing operation on mouse down or mouse up. There are typing aids to enter spaces between words or to capitalize sentences automatically.

More keyboard-related options can be found in the Keyboard control panel. These options may improve your typing experience, but they are not directly related to accessibility and therefore, will not be explained further here.

If you want to assemble your own keyboard panel, you can use the Panel Editor. We open the Panel Editor. We will create a button that will help us create a frequently used email template. We create the Email to John button, which invokes an AppleScript program. By the way, this is the source code of the AppleScript program we are using. Our mini keyboard needs a name, so we name it Email Templates.

You see that there are many more options for automising keyboard activities. However, explaining all the options would exceed the possibilities of this course.

We are leaving the editor. Let's try it. We start the Accessibility keyboard and select the Custom panels menu. We choose our new Email Templates menu. We press the Email to John key. The AppleScript starts the Mail program and creates a ready-to-use email template. We just need to add the message and the email is ready to go. This can save a lot of typing.

There are many more possibilities to configure your On-Screen Keyboard. You can use screen corners for activation and deactivation. You can configure the Dwell behaviour of the On-Screen Keyboard. Dwell Control allows you to perform mouse actions, such as left clicks, scrolling and drag and drop, using eye- or head-tracking technology. It works by resting, which is where the word dwelling comes from: The mouse pointer over on-screen buttons to perform corresponding mouse actions.

Explaining all these options would exceed the limits of this course by far.

Sticky keys and Slow keys

The Keyboard control panel offers us more functions. Imagine you can only use one hand and you have to type a combined key combination, like Shift-Control-Option-U. This would be really

difficult. When Sticky Keys is activated, the system adds all keystrokes that can be used in combination with other keys., like Shift, Control or Option, until a character key is pressed.So you can type Shift-Control-Option-U in sequence instead of at the same time, to activate this key combination.

Let's try this. I started TextEdit to type a text. I would like to select a word. So I position my cursor before the word and press Shift, then Option, then the right arrow key. The word is selected. Now I want to copy the word. I press Command, then the letter C. I reposition the cursor and press Command followed by the letter V. This was a copy-paste pressing one key at a time.

The control panel offers us additional options for Sticky Keys. We have the possibility to activate and deactivate Sticky Keys by pressing the Shift key five times, we can create an acoustic feedback once a modifier key is pressed. And we can customize if and how key presses should be shown.

Slow Keys allow the user to specify the duration for which one must press-and-hold a key before the system accepts the keypress. This feature prevents unintentional keystrokes caused by trembling motions.

Let's try it. We activate the checkbox Enable Slow Keys. I switch to TextEdit and start typing random keys. Nothing happens. I am typing too fast. So, let's try to press the single keys longer. Press and hold... release. Press and hold... release. Press and hold... release. This mechanism prevents us from making accidental keystrokes.

The Options dialogue allows you to set the time a key needs to be pressed until it is recognized as a keystroke.

Pointer controls

The Pointer Controls panel enables you to configure several pointing device related parameters. In case you cannot execute fast movements, you can configure the amount of time between two mouse clicks for it to be considered a double-click.

There are several more timing-related options here to configure mouse and trackpad behaviour. As this course cannot go into every detail, we will not explain them here. Feel free to experiment with them to see if they can improve your user experience.

For those who prefer keyboard-based navigation, you can enable Mouse Keys. Mouse Keys enable you to move the mouse using the keyboard. I am now moving the mouse pointer using the numeric keyboard. A mouse click can be created by pressing the number 5.

The Options dialogue allows you to configure several parameters when using Mouse Keys, for example the speed of movement. The Enable Alternative Pointer Actions function allows a keyboard key or switch to be used in place of a mouse button or pointer action, like left click or right click.

Switch control

Switch Control is a powerful accessibility technology for anyone with extensive physical and motor skill limitations. It helps you enter text, choose menus, move your pointer and more, all by clicking a switch.

You can use a keyboard key, mouse button, trackpad button, joystick or an adaptive device to simulate or implement one or more switches. Switch Control scans your screen until you click a switch. This single click selects an item or performs an action.

We select the Accessibility control panel and select Switch Control. As an example, we activate Switch Control via the mouse and deactivate it using Switch Control. To start it we activate the Enable Switch Control checkbox. After enabling Switch Control, the Home panel appears.

To cycle through items in the Home panel, press a switch such as your mouse button or the Space bar. Press the switch a second time to select the highlighted item. We want to use the Pointer mode. The system begins scanning horizontally. When the range finder highlights the area you want to click, click your switch again. Click again to refine your horizontal position precisely. The next click starts the vertical range finder scan. Click again to refine your vertical position. Click your switch a final time to click the element on the screen that is currently under the crosshair you created on the screen.

Let's try another mode. The App mode scans items and groups in the active window of the app in use. Let's try to deactivate Switch Control using the App mode. Please note that I am using just one switch, the Space bar on my keyboard. As you can see this works perfectly, but requires a lot of time. Switch Control offers several different scan modes and many options to choose from.

As Switch control requires a lot of training to operate all the different panels and modes, we will not explain them here.

Where to continue?

You have seen an introduction on how accessibility tools are integrated into macOS. There are many options for very different kinds of specific needs.

Depending on your personal interests you could continue with one of the following chapters:

  • Assistive Technology – Windows
  • Assistive Technology – iOS
  • Assistive Technology – Android

If you would like to learn more about screen readers in macOS, we recommend you continue with: Screen readers – macOS.

[Automated voice:] Accessibility. For more information visit:

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