User Manual LG Electronics MS4296OBC Microwaves

This microwave does have a cooling function to cool the interior of the oven after cooking is complete.

Thank you for this question about turning the sound off, not all microwaves are able to do this it's a safety feature to let the user know they have selected or pushed a button to bring this to your attention to what you have selected

i have been through this manual and there does not seem to be an adjustment for the tone, not all brands are able to do this, its done to let you know that you have depressed a function as a warning and that the button selected was the correct button for what operation you are wanting to do.