Noises a hedgehog makes are all very strange sounding. They can be intimidating to someone who doesn't know anything about them. Hediges are generally not very noisy, especially if they are kept signal.
They do make a wide range of noises, some of which i have still yet to hear.
 
Some are made out of aggression, displeasure, scared, mating, pain, & some many other reasons.
 
I have even heard that some hogs will make a number of the noises while sleeping/dreaming. None of mine have done that, but i think it would be CUTE!!!
(haha the gliders bark in their sleep quite often & i LOVE it!)
 
 
Hedgehog noises:
 
 
Light squeak to a chirp-  Normally made when a male & female have been put in a cage together & they are in the 'mating mood.'
 
Screeching or screaming- Made when in physical pain.
 
Hissing, clicking/popping- This is telling you they are scared & want to be left alone- distrust.
 
Puffing/popping/snorting- This is made when they are unhappy with you, something else, or they do not trust you or something else around them.
 
Sniffling- This is a meaning of being content & happy/exploring their surroundings.