I'm not sure if this is caused by Google Now or Moto Voice. This is a Moto X (1st Gen).
I am using Moto Voice. I have Moto set to Speak to me at Home and when driving.
When I am driving (or at home) it still does not provide voice output (" text from blah blah" or prompts in response to my speech (Text Bob, "What message do you want to send".). It no longer provides those voice prompts, Just a beep.