This is a very different question from the root parent. I used my first computer in the early 80s so my answers can relate to a very different world/context th

This is a very different question from the root parent. I used my first computer in the early 80s so my answers can relate to a very different world/context than ours now. First personal computer users had only experience with mechanical typewriters that made a lot of noise when typing. So 8bits computer keyboards usually have a feedback sound on each character. The sound was different in repeat mode and maybe backspace mode. On input validation failure, systems usually made an annoying beep sound. In the early mouse based GUI systems, the same kind of sound was used if you clicked outstide the current modal dialog box for example. So sound was used as some kind of error signal mostly. On the mac the system beep was replaced with a duck sound (or whatever it was configurable). Different sounds hinted the user if the message was some kind of error or an event notification. Until recently this may have an ergonomic value for some users. PCs used plain system beep for a long time. These days the motherboards still use them as error message for things like missing RAM...