Tony Morales, writing on the 10th anniversary since the introduction of VoiceOver for OS X:

VoiceOver, however, represents a significant milestone in the history of assistive technology. With the introduction of VoiceOver, Apple became the first operating system vendor to build a fully functional screen reader into the operating system that didn’t require additional installation procedures. Unlike Windows Narrator, VoiceOver didn’t simply follow the keyboard focus as the user navigated the GUI using available operating system shortcuts. Instead, VoiceOver provided a rich set of commands for interacting with the contents of the GUI, putting the user in the driver’s seat.

A fundamental technology for the Accessibility community, with an unwavering commitment by Apple. Today, VoiceOver is also available on the Apple Watch.