Buttons with a title, use it as its default accessibility label. Most cases, that's just perfect. But there's a few times that you might want to tweak it. Maybe the image is part of what the button does, or the text in the title is not very clear.

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Very often we need to show a UISwitch preceded with a UILabel that explains what it does. The text in the label is basically the accessibility label for the switch. Ideally we want for both components to be grouped behave as a UISwitch. It makes much easier to understand what the switch does, compared to having two separate accessible components. There is a number of ways you can do that. One of them is to use a container view and proxy the switch accessibility attributes.

You should convey important information in multiple modes, not just color. If you are still required to do so, at the very least you should complement that info with other modes, like symbols, if the user requested differentiation without color.
Guidelines from Apple: Begin with a verb that explains the results of the action. Avoid using the imperative form of a verb because that can make it sound like a command. Don’t include the action type. Don’t include the control. https://developer.apple.com/documentation/objectivec/nsobject-swift.class/accessibilityhint