Myth. It's an oft-used defense of police using choke-holds and ridiculous on the face of it. One can still be able to talk even though they are not getting enough oxygen. It's a frequent complaint of people having a heart attack, which Floyd might have been and which excuses the cop of murder not at all, since what he was doing can readily induce one. Floyd was dead when the ambulance arrived and according to their later report he had been that way for some time, was he faking that?