A number of Accessibility Services are available to aid in navigating your Android device. Each can be enabled or disabled via the Accessibility menu under Settings. The most popular services are described below:
TalkBack is one of the official accessibility services provided by Google. It uses synthesized speech to describe the results of actions, such as moving to a new control with the directional pad or clicking on a control, and events such as a notification or incoming call.
TalkBack comes preinstalled on most Android phones. However, it is under active development. You may want to download the app from the Market to get the latest features. Once you download it from the Market, you will be notified when updates become available. Note that TalkBack cannot be uninstalled.
Spiel is a third-party accessibility service that provides an alternative to TalkBack. It also uses synthesized speech to describe actions and events, but it has its own rules for speaking that may differ from TalkBack's. For more information on Spiel, see the Spiel Project webpage.
Spiel is not available from the Android Market. To install Spiel, follow the instructions in Market to enable non-market apps. Search for http://tinyurl.com/aspiel in your browser. While the url will load in the browser which is not accessible, it will automatically download the app. You can install it via the Notifications screen.
You can have both TalkBack and Spiel installed at the same time, and then enable whichever one you want to use. While it's perfectly safe to have both of them enabled, only one of them will actually work at a time. Spiel and TalkBack work very much the same way, so you shouldn't expect major differences. They're both being actively developed independently.
Voice Readouts is the Motorola accessibility service that is analogous to TalkBack and Spiel. It also uses synthesized speech to describe actions and events according to a set of rules.
Voice Readouts comes pre-installed on the Droid 2 and Droid X devices. You can enable or disable it via the Accessibility menu under Settings.
KickBack is one of the official accessibility services provided by Google. It provides haptic feedback by vibrating the device briefly when you perform an action on the phone.
It can be especially useful when using the touch screen. The feedback will inform you when you have found a valid control, like the slide-to-unlock handle. Additionally, it can be useful when navigating your device using a directional controller, as you know when your movement has resulted in an action. For example, when navigating through a menu you will feel a bump every time you hit a new menu item. When you stop receiving feedback, you know you have reached the end of the list.
On devices running Android 4.0 and above, the functionality of KickBack is included in TalkBack.
SoundBack is one of the official accessibility services provided by Google. It plays a short sound when you perform an action on the phone, such as moving to a different control using the directional controller, or clicking on a control that performs an action.
On devices running Android 4.0 and above, the functionality of SoundBack is included in TalkBack.
Android 2.2 includes a new capability for application developers to include enhanced text-to-speech capabilities in their app. If you have Android 2.2, you do not need to install anything.
If you have Android 2.1 or earlier, you can install an app called TTS Extended to take advantaged of these enhanced capabilities in apps that use them.
The various accessibility services are designed to complement one another. While you should normally only use only one talking accessibility service at time, the services that provide alternate feedback can be used simultaneously for improved efficiency. While there can be a slight delay before speech synthesis can talk after you perform an action, KickBack and SoundBack can provide much more immediate feedback.