Is it possible to pull a dialog substring from the scope of the running script, similar to $PrivateString but without changing the stack object to the source of the string? I want to display a dialog with the portrait of a neighbor and therefore need him in stack object.

I cannot understand what $BehaviorString:0:1 does. There is only one example of it in group 0x7F6A5174 and it references a table 0xF5 which I cannot find anywhere. I suspect that might be an internal table, but I don't see it in the Res\Text directory either.

An alternative is to take a string from Temp, but that requires supplying a much longer string where only a couple words change.

I was wondering that too but did not manage to figure out another way.

In the meantime, as an alternative version, maybe the TNS Style 0x05 notes might be of use to you. You will need some sort of object or icon to be placed into Temp 1 (or you could just leave it empty if nothing fits), but Temp 2 can be your Sim's nID and that's displayed on the left side of the text notification, which would be pretty close to what you want to achieve but would still allow you to have the Stack Object as the thing you wanna pull PrivateString resources from. I am not sure if this is Base Game-compatible, but I got this TNS Style to work with a game setup as low as Base+Uni+NL in a test for one of my own mods.

I'd guess that using $SemiGlobalString:X:Y might also work, since every Sim's character file includes a semi-global reference to the PersonGlobals. That'd require some testing though.

That is a nice discovery about the TNS.

Modifying person globals is not a "good form" because many mods want to change that group. If the neighbor is in the object (supposedly talking over the phone), then I can't access semiglobals of a person.