I truly wish I had a bibliography to give you but it has been so obviously true to me that I hadn't bothered to catalogue all of this information. I'll try to get you started though. Start by familiarizing yourself with the Snowden leaks and how the government buys data from private companies to violate the constitution. Second, look for articles like this one:
https://www.pcworld.com/article/2450052/do-smartphones-liste... This kind of thing is published periodically. Apple lost a lawsuit over Siri spying "inadvertently" very recently:
https://arstechnica.com/tech-policy/2025/01/apple-agrees-to-... There is no reason to believe that your phone is ever not listening. The audio can at least be transcribed and catalogued.
If companies are willing to track your every click and mouse movement, every footstep and slight movement you make with your phone even while you are asleep, build and bundle keyboard apps to capture what you type, monitor you with AI, etc., are you seriously surprised that they would not also listen to you? None of that stuff I just described is fiction. It's established tech that has been documented over time. The only reason it's not 100% illegal is because the EULA probably covers it.
I swear people who think they aren't listening when they can seem like people who would be shocked to learn that an armed carjacker might demand your wallet in addition to your car. Unreal...
Oh yeah one more tip. Try to use the data export feature from Google or Facebook. You might just be surprised what you find. I've heard of people finding recordings of private conversations picked up by Google devices. I personally found hundreds of Facebook messages and posts that I deleted with a tool, and aren't visible to anyone (OK maybe the messages make sense but not the posts).