I took a photo and then went into Photos, clicked on share and then messages. The message had the picture in it ready to go. I filled in the address and hit "return" so I could dictate the message. That didn't work so I typed it in. This has happened lots of times before, I just don't do it that often, so didn't think to ask about it.
After I read this I tried once again and this time Dictate refused to respond when I tapped the icon.
After several attempts, I resorted to the
universal fix and rebooted my iPhone. Dictate worked perfectly after that.
Not a fix, but at least a workaround. In the meantime, I submitted Feedback to Apple.
As shown under my original message, I have an iPhone 7, version 14.1.
Sorry I missed that before. This is the kind of issue that gives developers gray hair which is probably why it is still around in iOS 15.5. If they can't replicate it, how do they know what to fix?