Many people had doubts that Amazon, Apple, Google are listening their conversations through Alexa, Siri, Google Assistant respectively, and they were right in their suspicions.
All three of them have their so-called honest reasons for this violation to privacy act, to improve the performance after analysing the comversations.
Google has admitted that conversation could be listened when smart assistant hears a catchword, which is also true for Siri and Alexa...
Details of the Google employee's reports and how to improve the situations can be read in the shared link.
Have a nice day.