TalkBack is an Accessibility Service that helps blind and vision-impaired users interact with their devices more easily. This application adds spoken, audible, and vibration feedback to your device. It is a system application that was pre-installed on most devices and is updated when the accessibility service is improved. TalkBack is available for download at the Google Play Store.
Today Verizon is making an update available to add support for TalkBack to the HTC DROID DNA. After the update, you should be at Version 2.07.605.1 710RD. During the install, it will optimize all the apps on your phone to be more compatible with TalkBack.