I mean, you know how everyone carries a phone these days? If you use your voice, it could be potentially recorded.
So… we could just use sign language. Teach everyone sign language, use that whenever you wanna say something anti-government.
Its much easier to cover up cameras (or move out of sight) than to cover up microphones. And its unlikely people would want to leave their expensive phone in another room out of sight, so teaching everyone sign language seems like a straight-forward option.
Also, bonus: its very helpful for people with hearing problems if everyone knew sign language.
Phones are usually in your pocket. If you wanna leave it on a table, just put some random paper on top of it. How do you easily stop sounds from going to your phone? Probably not as easy as just covering up the camera.
This is under the assumption you are at home (or some safe place outside of public view), I mean why are you planning anti-government activities in public lol.