mk
Used to indicate acknowledgement or acceptance.
I promise to give it back. – OK.
Used to introduce a sentence in order to draw attention to the importance of what is being said.
OK, I'm thinking of a number…
Used in turn-taking, serving as a request to the speaker to grant the turn to the interrupter.
You always do this to me! When we were at your mother’s, you said that… – OK, OK, …