First and foremost if there was no sound then all living beings
who have the ability to hear on our world will lost their sense of hearing.
Making the sense of hearing or having ears useless (Because if there was no sound
at all then there was no vibration or pitches being detected by a hearing
senses).
But there are some good points in quietness.
Your other senses will get enhance. No more bad words and noises. Making all the people more physically fit
because if you want to convey something to someone without verbal
communication, you've got to use nonverbal to send a message just in case you
can’t write a word or text to someone.
There are going to be a lot of disadvantages if there was no sound;
less communication, no music, no song, no alarm clock, less warning when you’re
on the road, some animals that rely on sound to communicate will surely be in
danger, and making the world a boring but dangerous place to live in.