Laryngitis is the inflammation of the larynx, which contains the vocal cords. When those vocal cords become inflamed, your voice often turns hoarse and may all but disappear.
The U.S. National Library of Medicine lists these common causes of laryngitis:
The common cold or flu.
Bacterial or viral infection.
Bronchitis.
Pneumonia.
Allergies.
Chemical irritation.
Injury to the larynx.