Guard llamas communication to sheep and humans in a variety of ways. I find that a snort or clucking my tongue usually gets their attention. I haven't needed to resort to spitting. We all get along pretty well here.
One of my favorite things to do is the chasing game. The sheep will run out of the barn and I will prance after them. The sheep will run back the barn and we start again. Sometimes the lambs try to trick me and split off in different directions. I just keep prancing around and they come running back because they don't want to be left behind.
Once I've had enough of that game, I cluck my tongue and everyone gets the message.
I haven't had to use my alarm cry very often. I can make a noise through my nose that sounds like a giant prehistoric bird. It's pretty impressive. When I sound the alarm, that means a predator is nearby and all the sheep run into the barn.
Communication is the key to being a good guard llama.