What is human beatboxing?

Beatboxing is a form of vocal percussion which primarily involves the art of producing drum beats, rhythm, and musical sounds using one’s mouth, lips, tongue, voice, and more. It may also involve singing, vocal imitation of turntablism, the simulation of horns, strings, and other musical instruments.

Standard Beatbox Notation (SBN)
The Three Basic Sounds
Putting the three basic sounds together