Linked from
The 22 pages that link to Vocal folds, each with the reason it gives.
LarynxBroader topic: Airflow sets them vibrating to generate the larynx’s sound source.
SingingBroader topic: Their vibration creates the sound source whose pitch singers control.
Vocal performanceBroader topic: Their vibration is the primary sound source for ordinary singing.
PassaggioBroader topic: Changes in vocal-fold vibration help shape register transitions.
KazooBroader topic: Their vibration creates the voiced sound that excites the kazoo membrane.
MutenessBroader topic: Their vibration is one physical step required for ordinary voiced speech.