Air pressure system

Diaphragm, chest muscles, ribs, abdominal muscles
Lungs

Provides and regulates air pressure to cause vocal folds to vibrate

Vibratory system

Voice box (larynx)
Vocal folds

Vocal folds vibrate, changing air pressure to sound waves producing "voiced sound," frequently described as a "buzzy sound"
Varies pitch of sound

Resonating system

Vocal tract: throat (pharynx), oral cavity, nasal cavities

Changes the "buzzy sound" into a person's recognizable voice