My iPhone 11 has a pink to red microphone in the upper left corner?
When The little microphone icon appeared, my dictations started duplicating everything I said. The microphone icon is the size of the location icon in the upper left at the very top and to the right of the time. I was experimenting with AssistiveTouch and think it was some setting there; but me and somebody from Costco at the Celular center tried to figure it out for about 45 minutes and could not get it to go away. It was nice as all my commands were immediately acted upon, and did not need to say hey Siri; but, when I hit the microphone icon in the bottom right to dictate a message, the words would be duplicated and sometimes mixed together creating peculiar sentences.
Hopefully somebody here will know how I got that turned on, as we could not figure out how to control that microphone icon which appeared after experimenting with assistive touch, and looking at all the commands for manipulating text and so forth, which worked fantastically.
I suspect it was listening all the time to whatever was said and waiting for a correctly worded command to implement. This was a brand new iPhone 11 with the last 2 - iOS 13 updates implemented.
Best,
Seth