Some news story contains this:
"'I could say that I have done some of those things,' he said of the accusations against him. "
How is "say of" different from "say about" or "say to"?
There is little or no difference between "said of" or "said about" or "said regarding."
However, "said to" is not right -- you say something TO a person.
I'm not a teacher, but I write for a living. Please don't ask me about 2nd conditionals, but I'm a safe bet for what reads well in (American) English.
emsr2d2 is exactly right. Unless, of course, you had something like this in mind:
Q: What would you say to a drink after work?
A: Hello. Would you mind terribly if I drank you?