Voice or voicing is a term used in phonetics and phonology to characterize speech sounds, with sounds described as either voiceless (unvoiced) or voiced. The term, however, is used to refer to two separate concepts. Voicing can refer to the articulatory process in which the vocal cords vibrate. This is its primary use in phonetics to describe phones, which are particular speech sounds. It can also refer to a classification of speech sounds that tend to be associated with vocal cord vibration but need not actually be voiced at the articulatory level. This is the term's primary use in phonology when describing phonemes, or in phonetics when describing phones.

At the articulatory level, a voiced sound is one in which the vocal cords vibrate, and a voiceless sound is one in which they do not. For example, voicing accounts for the difference between the pair of sounds associated with the English letters "s" and "z". The two sounds are transcribed as [s] and [z] to distinguish them from the English letters, which have several possible pronunciations depending on context. If one places the fingers on the voice box (i.e. the location of the Adam's apple in the upper throat), one can feel a vibration when one pronounces zzzz, but not when one pronounces ssss. (For a more detailed, technical explanation, see modal voice and phonation.) In most European languages, with a notable exception being Icelandic, vowels and other sonorants (consonants such as m, n, l, and r) are modally voiced.

Peter Griffin is a fictional character and protagonist of the animated comedy series Family Guy. He is voiced by cartoonist Seth MacFarlane and first appeared on television, along with the rest of the family in the 15-minute short on December 20, 1998. Peter was created and designed by MacFarlane himself. MacFarlane was asked to pitch a pilot to the Fox Broadcasting Company based on Larry and Steve, a short made by MacFarlane which featured a middle-aged character named Larry and an intellectual dog, Steve. After the pilot was given the green light, The Griffin family appeared on the episode "Death Has a Shadow".

Peter is married to Lois Pewterschmidt and is the father of Meg, Chris and Stewie; he also has a dog named Brian. He has worked at a toy factory and at Quahog's Brewery. Despite the suburban blue-collar routine of his life, he has had a number of remarkable experiences.

Peter's voice was inspired by a janitor that MacFarlane heard at his school. His appearance was a redesign of the protagonist Larry from MacFarlane's previous animated short films, The Life of Larry and Larry & Steve. The Peter Griffin character has received generally mixed to positive reviews from critics. He has appeared in several pieces of Family Guy merchandise, including toys, t-shirts and a video game, and has made crossover appearances in other shows, including The Simpsons, South Park, American Dad and the Family Guy spin-off The Cleveland Show.