You may think you are ok using home devices such as Google Home or Amazon Echo but maybe not so much. Security Research Labs in Germany has some videos that will show how the devices are still active even after you think they have stopped listening.
In this video you can see the person talking on the right and the information recorded in the terminal on the left. As she keeps speaking after the time of her first question, it keeps recording the information to the server.
You will see it continued to record after the person said “Alexa stop”.