You probably know that Google keeps track of everything you typed in the search window, just as it scans your email to "analyze content".
But what you may not know is that Google has also registered you, as the Guardian writes. Recording is not necessarily done in the NSA's way, for which Eduard Snouden has spoken clearly.
However, if you have used Google Voice Control features (you usually do so because you say "OK Google"), everything you've been talking about in this service has been registered. Fortunately, Google lets you listen to yourself and clear that story.
If you visit the Google History page and go to the Voice & Audio Activity button, you can listen to what you requested from Google and delete it all. You can also change the settings to make sure it does not register you again. There have been suggestions that Microsoft's Siri and Cortana have also recorded what the users say, but apparently there is no way to delete those records.
Amazon Echo is supposed to be the worst of all these services, seeing the census is at the center of everything it does. However, you can also clear the story to Amazon Echo