The challenge you have is not language related, but rather logic related. The issue our Swiss friend raises is valid, no matter the language.
Do Americans not have an expectation of privacy even when talking in public, based on the expectations of the individuals engaged in speech?
For example, when you are at a restaurant with friends, is there not an expectation of privacy within the context of your conversation with someone? Any reasonable person will have an expectation of privacy that will generally be limited to all those people around your table and with whom you will be making eye contact, as long as you are speaking at a tone that is reasonable for that context. No? Is the speaker going to be speaking so that everyone in the restaurant can understand their speech? No? So it’s not public then, right? Ignoring incidental overhearing, of course.
Inversely, if we consider what the American system clearly considers private, the home and, by extension, the car; if you have ever heard a conversation through thin walls between apartments or maybe a phone conversation on car speaker blasted speakerphone, is that private then? … are Phone conversations then also not private since in most cases the caller will not likely be aware that their direct conversation partner is blasting their conversation to the parking lot on the car’s speaker phone?
These scenarios, among others, beckon a requirement to make privacy expectations approaching unachievable. Is that reasonable? No, of course not.
And that’s before we explore things like focused beam microphones that make all conversations within any line of sight or even just things you whisper into someone’s ear not radically private based on the current American nonsensical definition reasonable and privacy.
The problem in America is not the speech part, but rather that the logic and reason itself has been inverted and perverted by sophists and abusive manipulators over the decades, which have turned everything upside down, including the definitions of “reasonable”, “public”, and “private”, i.e., the core logic of the matter.
None of the founders of America and the writers of the Constitution would recognize any of these current assumptions built into definitive and even the words they wrote, let alone all the illogical and lazy cruft that has been added after the twelfth amendment. They would think we’ve gone insane, because were have our, more accurately, sophist psychological manipulators and abusers have driven us so insane that we engage in the horrid abominations and abuses that are normalized all around us today. It has long been an ever worsening entropy problem.