How else would they be able to tell you how busy a location is when you pull it up in Google Maps?

This one works with Wifi SSID lists I believe. No need for audio.

My partner knows french but never speaks french on a regular basis because we met and started dating in another spanish, so spanish tends to be our default language. Whenever for some reason we speak french for a significant amount of time she starts seeing ads in french about french brands on the web and social media apps while all her devices are in spanish and we are living in Spain.

Same when we talk a lot about a particular subject. We found out she starts seeing ads quickly on related stuff.

I am not sure if it comes from android directly, her social media apps or both but something is definitely listening and analysing audio.

Which leads me to think that all FAANG and social medias companies should be sued to death because they actually ask permission to the owner of the device to get and treat personal data, but never to the people who meet them. Especially in the case of amazon echos and google home devices. A number of times when people invited me at home I raised the subject that they never warned me they had a privacy aspiring device set up at home before letting me in and I was met with puzzled looks.

I have seen so many claims like this one, yet never any evidence of this sort of thing actually happening. I tend to believe this is a combination of confirmation bias and "side-channel" information like googling related things, or pattern recognition on the ad server's ML side (e.g. if you visit the amazon toilet paper section once a month, and after almost a month you start talking about toilet paper, getting served toilet paper ads might seem suspicious, but it really isn't).

Is there any actual information about this somewhere? With the insane breach of privacy policies and laws this would be, I would think many researchers would have looked into this by now.

No evidence I’ve ever seen, and people have looked at the communications pretty extensively. I think it’s hust a very compelling conspiracy theory born out of the “whatever you pay attentiom to seems to happen more” principle. My s/o became obsessed with the idea that Tesla cars are hugely dominant, and if you ask her Tesla probably has 90% market share, just because that’s all she sees.