The vocal folds, also known commonly as vocal cords, are composed of twin infoldings of mucous membrane stretched horizontally across the larynx. They vibrate, modulating the flow of air being expelled from the lungs during phonation.

Open during inhalation, closed when holding one's breath, and vibrating for speech or singing (oscillating 440 times per second when singing A above middle C), the folds are controlled via the vagus nerve. They are white because of scant blood circulation.

Birds do not produce vocal sounds by means of vocal folds but by oscillations of membranes in the syrinx.

The larynx is a major (but not the only) source of sound in speech, generating sound through the rhythmic opening and closing of the vocal folds. To oscillate, the vocal folds are brought near enough together such that air pressure builds up beneath the larynx. The folds are pushed apart by this increased subglottal pressure, with the inferior part of each fold leading the superior part. Under the correct conditions, this oscillation pattern will sustain itself. In essence, sound is generated in the larynx by chopping up a steady flow of air into little puffs of sound waves.

Melvin Jerome "Mel" Blanc (May 30, 1908 – July 10, 1989) was an American voice actor and comedian. Although he began his nearly six-decade-long career performing in radio commercials, Blanc is best remembered for his work with Warner Bros. during the "Golden Age of American animation" as the voice of Bugs Bunny, Daffy Duck, Porky Pig, Tweety Bird, Sylvester the Cat, Yosemite Sam, Foghorn Leghorn, Marvin the Martian, Pepé Le Pew, Speedy Gonzales, the Tasmanian Devil, and many of the other characters from the Looney Tunes and Merrie Melodies theatrical cartoons. He later worked for Hanna-Barbera's television cartoons, most notably as the voice of Barney Rubble in The Flintstones and Mr. Spacely in The Jetsons. Having earned the nickname “The Man of a Thousand Voices,” Blanc is regarded as one of the most influential people in the voice-acting industry.

At the time of his death, it was estimated that 20 million people heard his voice every day.

Blanc was born Melvin Jerome Blank in San Francisco, California, to Jewish parents Frederick and Eva Blank. The youngest of two children, he grew up in the neighborhood of Western Addition in San Francisco, and later in Portland, Oregon, attending Lincoln High School. Growing up, he had a fondness for voices and dialect, which he started to do as early as the age of 10. He claimed that when he was 16, he changed the spelling from "Blank" to "Blanc" because a teacher told him that he would amount to nothing and be, like his name, a "blank". Blanc joined The Order of DeMolay as a young man, and was eventually inducted into its Hall of Fame. He dropped out of high school in the ninth grade and split his time between leading an orchestra, becoming the youngest conductor in the country at the time at 17, and performing shtick in vaudeville shows around Washington, Oregon, and northern California.