There are speakers that plug directly into the headphone jack. Slightly louder than built-in speakers. The plug is easy to break if you're not careful.
There are speakers that draw power from the USB jack. Shaped like cubes about 2 inches on a side. A major step up in quality and volume compared to built-in laptop speakers. Can be heard in a noisy room. Easily portable.
Desktop speakers vary in quality. Some have bass (or treble) boost switch. Mine have a separate power supply. They switch themselves off 15 seconds after playback ends, making a loud click.