I can do that my phone read the number of incoming text messages.
Tip: Tap Read aloud incoming text messages, and then choose when you want to hear the announcements—all the time, or only when using a Bluetooth and/or a wired headset.
I dont think WP7 or 7.5 can do it. Why would you want it read all the time? Are you always alone and in a place where your phone can just read you incoming text messages aloud?
I dont think WP7 or 7.5 can do it. Why would you want it read all the time? Are you always alone and in a place where your phone can just read you incoming text messages aloud?