This will be a life saver -- literally -- for folks who use their handsets while on the go (driving etc.) and have Bluetooth headsets on. Mango will be taking speech recognition beyond simple app opening commands. Should you receive an SMS, the phone will announce via speech stating who the text is from and ask if you would like to hear it. You will then (should you choose to say so) be listening to the message your contact sent you.
Not only do we have text to voice, but we have voice to text. Should you say "reply" once the phone has completed reading you the message, you can then record your reply and it will preview what you've said. On confirmation the text will be sent to the recipient. All hands-free.