Alicornutopia

I know it would have derailed the whole plot, but I wish Jack had pinged as Jacob's name.

Yeah, that would have been convenient. Just like the “Am” from “Amy” pinging as Amelia’s name. They just aren’t quite pronounced the same way.

I thought common nicknames ping, but you're right, Amy is also a common nickname/diminutive for Amelia.

//So where's the line? Does Dick ping for Richard or Bill for William, Sasha for Alexander?

It needs to be a strict phonetic shortening.

EDIT: Link!

EDIT 2: Similarly, Cherie doesn’t quite share a syllable with Cherish, so I doubt she could get the one from the other even though they’re close. This is further confounded by the fact that she’d need to strip the second syllable from Cherish before even trying to match it to the name, and by the fact that Cherish is a word and her plainspeaking might get in the way of manipulating it at the phonetic level.

I would've expected the -my of Amy to ping to the -me- of Amelia, actually. But maybe the pronunciations are just-sufficiently-different.

In "Amy", the "my" is unstressed; in "Amelia" it's stressed.

Promise could brute-force enough of "Jacob" with sounds she already knows to appear in human names ("Jack" and "Jac-" differ only by vowel, and that vowel appears in "Amy"), but she doesn't know that would work so she'd have to be low on other options to try it.

Dragons who turn into sprites wind up as one of the two reproductive genders, not as workers. Dragons who turn into earthworms wind up earthworms.

Your healing trigger word is "Mulaglarby". It's hard to say by accident.

Would accidentally saying it cause problems? The only one I can imagine would be if you were in the middle of fighting somebody and then accidentally healed your opponent, but I thought they didn’t fight Neuroi in close-enough quarters for that to happen.

It's just a general safety practice for trigger spells.

Somebody should probably be expanding the nickname "Jack" for Promise in case the long form is his name, no?

Expand it to what? Johnathan? James? Jacques? Each failed attempt is more mortal names she knows, and there’s a good chance his real name isn‘t any of them. They should consider the possibility, but I don’t blame them for deciding not to follow through on it.

On the other hand, Dragon should be able to figure it out. I don’t think he did that good a job anonymously the records.