When someone sends you an SMS or IM, you see their name and picture if they are in your contacts list, and the name of the app that was used to send it.
Voice control announces the message and who it is from.
Select Read Aloud to have the message read to you by your device.
If you selected the message itself, you see the following options:
Reply - select this button to reply using a predefined message such as Sorry, can't talk now. (Android phones only.)
Read Aloud - select this button to have the message read aloud.