The way to spell out a more complete explanation comes a few hours later. They have a board with lots of letters. "Do you want to spell something out?"

.......blink blink blink.

"Have you encountered the concept of writing before?"

Blink.

"Do you know how to write in some alphabet?"

....blink blink blink.

"Okay. So, the idea of writing is that you make a letter for each sound in the word, and then when reading you make the sounds and figure out what word it is." She explains the sounds that each of the letters represents. "Does that make sense?"

Blink blink!

"Maybe we should do an example? So imagine I wanted to spell out "I am an exotic sort of fairy that can only speak at night". That starts with "I". So first I'd blink when someone was pointing at this letter, because I said that letter sounds like "I". The next sound is æ, so you'd blink for this letter. Does that make sense?"

Blink blink.

....will an hour of attempts in this vein get anywhere?

It will get her acknowledging that a greater fraction of the concepts involved make sense but otherwise no.

This person is so frustrated and (once the others have wandered off) sad and scared. Eventually she gives up and sits down and cries quietly.

Well, Promise kind of wishes she'd just fucking let her talk already but she is way too confused to do that apparently.

Much too confused.

A different group of people come with a new barrage of questions. 

"Are you a fairy?"

Blink blink.

"Are you a mortal?"

Blinkblink.

"Is there some other kind of person?"

Obviously you moron. Blink.

"Is your kind of people faster than us?"

Blink blink blink what the fuck does that mean.

"Uh.... we are faster than mortals. That means we can see them but they can't see us, and to us they appear to go about their lives very very slowly, doing only a few things between sunrises, when we can do many thousands. If you were faster than us, you'd have noticed us, being all but still."

Blink blink.

"Okay. Uh, since you are not a fairy, you might not have the concept of debt. Do you know what debt is?"