The ceilings one is way simpler.
When you spend a lot of time in a place with low ceilings it makes you subconsciously feel trapped. After a while of it your actions and behavior will likely start to reflect that and you will probably be less likely to do anything that you can for your future.
You don't get that in a place with higher ceilings.
I've never actually heard them vocalize anything. I've heard them whistling and the time they chased us out of the forest they made this like expelling a ton of air sound.