How do people talk to each other in Inform?

I can’t seem to make NPCs respond to the player talking to them.
This is the entirety of my code:

[code]“Test” by MK

The Place is a room.

Sally is a person in The Place.

Instead of saying Hi to Sally: say “She responds, ‘Hey, what’s up?’”[/code]

This produces an error saying that it looks like I’m trying to describe a rule that occurs after a player action, but “saying Hi to Sally” doesn’t make sense as an action. This occurs if I use before, after, when, and report. I experience no change
Conversely, opening Sally and having her say something in response works totally fine, as does making an item and giving said item to her. It’s only when I try to use “saying” or “telling” or equivalent that I get an error.
What the crap?
Just to be clear I’m trying to make it so the player can enter “Say hi to Sally” and have her respond “Hey, what’s up?”, as opposed to the player doing something like, “tell Sally about hi”.

The action of saying something to someone is actually “answering it that” (see the actions tab in the index page), so the wording you’re looking for is

Instead of answering Sally that "hi": say "She responds: 'Hey, what's up?'".
(For more info, see chapters 7.6-7.9 in the Inform Recipe Book.)