Could you get people to use the NATO phonetic alphabet for the spelling part? I suppose a challenge is that many people don't know the whole thing, even if they're aware it exists.
air a
bat b
cap c
drum d
each e
fine f
gust g
harp h
sit i
jury j
crunch k
look l
made m
near n
odd o
pit p
quench q
red r
sun s
trap t
urge u
vest v
whale w
plex x
yank y
zip zb) Talon Voice is a configurable voice engine, the commands are something you setup and people use common shared starter packs and then edit their own, so there isn’t a formal standard, plex might be different in some setups?
c) they just have to be sounds you can vocalise which are distinct from each other, and it helps if they are one syllable when using them often; there’s no reason they have to be dictionary words or mean anything.
One could make "Pit" be "t", with that logic.