I'll never recommend creating a custom component if there is a native one that does the job. But if you develop a custom tab bar, .tabBar accessibility trait comes to the rescue. Apply to a container view and its buttons will be announced as tabs.

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If you want to keep yourself up to date with what’s going on, or what has been published lately, on how to develop more accessible mobile apps, make sure you subscribe to Accessible Mobile Apps Weekly by @RobinKanatzar from @accessible_apps.
@azzoor has this great video with some advice on how to set up your device for testing accessibility and a ton of tips will get you testing effectively in no time. https://m.youtube.com/watch?v=Ca1H6wF348g&feature=youtu.be

Today I want to share something I use a lot. You can convert any article into a “podcast” by enabling Speak Screen in Accessibility Settings, switching to Safari’s Reader Mode and swiping down with two fingers from the top of the screen. I think it is a good example of how if we all knew more about how to use the assistive tech available in iOS, we would find ourselves using more of them, more often, exemplifying quite well that accessibility benefits everyone.