LOL. They only spit when they get uppity with each other. There was a story in a local paper a few years ago about a woman who did llama pack trips. IIRC, the company was called "Spit Happens."
My next-door neighbour is seriously into fiber and weaving. She has downsized now to 8 alpacas (bear attacks a couple of years ago took 4
) but she had about 30 alpacas and llamas a few years ago. They used to use my property as well as hers for grazing and kept the Scotch broom completely under control 
When they are curious, they emit short "hmmms". I took a nap out in the field once and awoke to see them in a circle around me, "hmmming", wondering that the usually bipedal creature was doing lying immobile on the grass.
