The /dev directory highlights how everything is a file or directory in linux, in /dev all computer objects are represented as “block” or “character” devices
Block Devices
Character Devices
Store Data
Disk Drives
SS Drives
Optical Drives
Stream Data
Serial Ports
Mice
Printer Ports
On older systems you could try '$ cat /boot/vmlinuz > /dev/dsp' to hear a sound on the speaker. You can still send a sound to your speakers but you have to look up the command specific to your computer and Linux Distribution