You can verbalize it as clearly as you can. You can speak it, shout it, whisper it or scream it. The covert abuser will hear what they want to hear. When they respond back to you, you wonder if they misheard or if you used the right words. You turn around to see if they’re speaking to someone behind you, because clearly they aren’t responding to what you said.
Doesn’t matter what you said or how you said it.