This is basically the trick to it. You have to define "sound" in order to answer this question.
So if you have two people who seem to disagree,
"Does the tree make a sound?"
"No! [because I define 'sound' as what happens when the ear detects vibrations]"
"Yes! [because I define 'sound' as what happens when vibrations are sent through the air]"
it's not because they disagree on what happens, but because they are defining the words in the question differently. And unless that difference is addressed, it's difficult to resolve the argument because they'll be shouting past each other --
"I think vibrations are travelling through the air!"
"NO, I don't think the vibrations are being detected by anyone!"
"Yes, vibrations are travelling through the air!!"
To me, that's actually the most interesting takeaway of this problem -- it can be applied to like... a lot of actual relevant arguments in real life. Two people who seem to be yelling past each other are, a lot of times, actually disagreeing on how a word or idea is defined, but when it's hidden inside another question like that, it can be easy to miss, and that's when a conversation gets frustrating fast.