Compared to many other livestock, llamas are very quiet animals. Humming is their primary means of vocal expression. A llama's hum sounds similar to a person's hum. Depending upon the situation, llamas may also cluck, orgle or make an alarm call.
All sounds are very distinctive and easily recognizable.
It will be clear what llamas are trying to express if you look at their situation and listen. Llamas are herd animals and are excellent at communicating with each other. They are so good at it that many of their subtle cues may be missed by an unaware eye. Take the time to watch and listen to your llamas to learn a little bit of their language. We expect them to understand what we want from them, it is only fair that we return the favor.