Feedback on form errors

This content needs to be rewritten and expanded.
Related issue on GitHub #161 Feedback on form errors.

Provide accessible notifications

When a dynamic event occurs, it should be announced audibly by screen readers. A dynamic event is any event that is reacting to a user without a page refresh: either a direct scripted validation or an AJAX request.

A good way to announce dynamic notifications in WordPress is using wp.a11y-speak(). This JavaScript function is included in WordPress core and enables you to announce dynamic changes and notifications to screen reader users.