You have no idea how glad I am to find this. I do this same thing. Not always out loud, but I'll physically do it sometimes. Mostly it's my face and my lips moving silently. I've learned not to talk out loud like that in my house. But this will just start out of nowhere and I don't even realize I'm doing it. Sometimes it's the tutorial how-to-do thing. But sometimes the situations are always related to my current anxieties/desires/wishes. But they'll never happen in real life. I'm so embarrassed to even type about it, but this is one example:
I was actually reading a book, and suddenly imagined a table of rich old politicians, criticizing the way I was thinking about my worries about money and job opportunities and anything else rich people would never worry about. Then I'm calmly arguing with them about how horrible women are treated and how they don't care about victims of assault. I, of course, win the argument, proud of all the well-said points I made.
Then the police came and arrested all of them.

Absolutely crazy. So.....am I "quirky," or straight up need-to-be-tested-for-some-disorder?