Siri has quit speaking, but displays text response. Nothing obvious wrong.

You click on Siri in settings, then click Siri Voice. Tap on another voice. You have to wait a minute because the new voice has to download. You must have an internet connection - WiFi or a Data time as part of your phone provider package. After you download a new voice from the list, for instance, British, or Australian it should work. Also I found that switching to the opposite Male/Female from what you have also works. I switched from American/female to Australian/female and Siri’s voice is back. So if you lost Siri’s voice suddenly, and the settings were not changed, I found this is the only fix, and it is simple.