"and hooo" drawn out in a low tone = halt or slow
"and walk" drawn out in a low tone(downward transition to walk)or "walk on" in a clear, energized, but calm voice tone(upward transition to walk) = walk
"and tru-rot!" said in a energized voice, sounding out the syllables (upward transition) or "and truuuot" said in a low tone, slightly drawn out(downward transition) = trot
"and canter, up!" the 'up' said in a slightly higher, energized tone = canter
(the "and" in the above is to prepare the horse, like a vocal half halt)
"Come" or clicking = more impulsion
^I use all the above when lunging. It's what we use at our barn, so pretty much every barn horse responds to them. Sometimes I use them while riding to help to horse understand what we're doing.
"Back" used with pressure applied to the chest, halter, or bit = backing up
Clicking, sometimes with pressure on any part of the body = moves away from pressure (like when I move her over to groom her or close gates)
Kissing = I only do this when we're cantering or galloping and she responds with more speed
"Good girl/boy" = general praise for anything done well, usually applied with many pats
"Come" = this version (used on the ground) means 'come towards me'
"Easy" and "You're fine" said in a low, calm tone = used to calm the horse on the ground or while riding
I'm interested to see what voice commands you and your horse(s) use. ;)