iPhone Dictating Speech Without Dictation Turned On

Thanks for the reply. I obviously did not describe the issue clearly. With my texting app open, I was having a conversation with someone in the same room, and the iPhone transcribed my speech into a text message without my direction. I am now thinking I should simply turn off "enable dictation" under Keyboard settings.

I have never noticed that dictation icon before now. Thank you for solving the mystery.