Laryngitis is an inflammation of your voice box (larynx) from overuse, irritation or infection.
Inside the larynx are your vocal cords — two folds of mucous membrane covering muscle and cartilage. Normally, your vocal cords open and close smoothly, forming sounds through their movement and vibration.
But in laryngitis, your vocal cords become inflamed or irritated. This swelling causes distortion of the sounds produced by air passing over them. As a result, your voice sounds hoarse. In some cases of laryngitis, your voice can become almost undetectable.
Laryngitis may be short-lived (acute) or long lasting (chronic). Most cases of laryngitis are triggered by temporary viral infection or vocal strain and aren't serious. Persistent hoarseness can sometimes signal a more serious underlying medical condition.