Hedgehogs have an effective way to tell predators to leave them alone: They curl up in a ball and let their quills stand out as a prickly discouragement. Hedgehogs use some body language when communicating with each other, but they also make several sounds to share how they're feeling.
Hedgehogs like to be alone, and they don't like other hedgehogs hanging around their territories. They sometimes fight to force another hedgehog away, and it's common for males to fight during mating season. When a hedgehog is about to charge, he makes clicking and popping sounds in warning. He might also make a dry coughing sound, then move into the body language phase. An aggressive hedgehog will sniff his opponent, charge and head butt another hedgehog to force him to leave.
Even solitary-loving hedgehogs need some companionship during mating season. When a male spots a female, he walks in circles around her with his nose pointing in toward her. This tells her he's interested. She ignores his advances for several days before deciding whether his wooing is adequate.
A healthy hedgehog with a full belly is a happy hedgehog. He expresses his contentment with little sneezes, snuffling or wheezing. He might also purr or whistle softly. Some whistles signal the location of an abundant food source, which can draw other hedgehogs.
Sometimes hedgehogs aren't in a fighting mood, but they don't want to be bothered by other hedgehogs. To express annoyance, a hedgehog might make huff and puff sounds, or he might hiss. He might also lift the spines on his forehead as a warning to other hedgehogs that he wants to be left alone.