WordPress 4.2 is shipping with a useful new JavaScript method: wp.a11y.speak(). This is a utility to make it easy for WordPress core to create consistent methods for providing live updates for JavaScript events to users of screen readers – with the side benefit that developers of plug-ins and themes can also make use of it either on the front or back end.

Source: WordPress › Let WordPress Speak: New in WordPress 4.2 « Make WordPress Accessible

One of my favorite changes coming in WordPress 4.2 is a new accessibility API to help with communicating changes on the page to Screen Readers. Core is using it in a number of places (including shiny updates) to improve the experience for users of screen readers. I’m excited to see plugins start taking advantage of it as well. The first step in accessibility is making something usable. The second is making sure the experience is top notch. This helps support step two.