It is really hard to explain, but once you hear it, you won't forget it. Gliders can make a sound like a barking puppy. I've heard they make it a lot when they are playing with each other. Mine has only done it a few times. A couple of times when she is playing with me, hiding behind the pillows, and a couple of times I have heard it when she is sleeping.
Gliders are a lot of fun - but they are a lot of work.
I have kids e-mail me all the time asking me to talk their parents into letting them have one as a pet. Like I tell them, in my opinion, a glider is not a pet for a child. Mine does not wake up until atleast 10pm. When I let her wake up on her own, she is so friendly and cuddly. If I wake her up early - she just kind of stares of into space, and has even been known to hiss.