I used the word "rehearse" cause there was a time in my life, a time of high anxiety and paralyzing social phobia, when I did rehearse what I was going to say, when I saw a conversation on the horizon. So when the time came, I could depend on reciting my lines, while the better part of my mind was occupied with steadying myself. I was probably more than a bit of a bore, and it was Hell on any sense of spontaneity or true conversational exchange. But it got me though a tough period. That's in the past. But on occasion, I still make up and revise dialogue in my head, (playing both parts). It usually happens in anticipation of a somewhat fraught interaction.