Google TalkBack

Google TalkBack aims to improve blind and vision-impaired users' day to day life, by using tech-related solutions. 
The app makes it easier for these users to interact with their devices using their voice to call on actions and their earring to get feedback. 

You will receive spoken, audible or vibration feedback according to the action you're looking for and be able to better interact with your device. In case you're having any problems with your app, you can reach Google's support service by visiting the website: https://support.google.com/talkback/ 

Google Talkback is already pre-installed in almost every Android device, and you can turn it on by going to settings, and selection the accessibility menu. If you are using Android 4.1 and above, you just need to touch Talkback and switch it on. 

If you're device is paired with Android 4.0, on the accessibility menu, touch Talkback to switch it on and then go back to the previous scree to select Explore by Touch. You're app is ready to use now. Lastly, if you are using Android 3.2 and earlier, select both the Accessibility the Talkback checkboxes. 

Please note that this is an accessibility app, which means it can observe your phone state to make it adapt announcements to your call status as well as retrieve window content and check text as you type.