FOUND ISSUE AND FIX!!
I had this exact problem, Google now was no longer reading out search responses. I tried every fix I could find (changing languages, clearing cache, making sure speech output is on, media volume is on, etc...etc...) and nothing worked. FINALLY I found the problem. A few backs in efforts to fix an audio sync issue with youtube I had turned on (checked) Use NuPlayer (experimental) in Developer option>Media. I simply uncheck it and google now is responding in speech to all my searches as it did in the past. Very happy to hear her voice again (creepy). Anyways hope this helps anyone else with this issue.