Kenneth "Kenny" McCormick is a fictional character and one of the four main protagonists in the adult animated sitcom South Park, alongside Stan Marsh, Kyle Broflovski, and Eric Cartman. His often muffled and incomprehensible speech—the result of his parka hood covering his mouth—is provided by co-creator Matt Stone. After early appearances in The Spirit of Christmas shorts in 1992 and 1995, Kenny appeared in South Park television episodes beginning August 13, 1997, as well as the 1999 feature film South Park: Bigger, Longer & Uncut, where his uncovered face and voice were first revealed.
Kenny was a third, later fourth-grade student who commonly has extraordinary experiences not typical of conventional small-town life in his hometown of South Park, Colorado, where he lives with his poverty-stricken family. Kenny is animated by computer to look as he did in the show's original method of cutout animation.
The character gained popularity thanks to a running gag during the first five seasons of the series, whereby Kenny would routinely suffer an excruciating death before returning alive and well in the next episode with little or no explanation. Stan would frequently use the catchphrase "Oh my god! They killed Kenny!", followed by Kyle exclaiming "You bastard(s)!". Since the sixth season in 2002, the practice of killing Kenny has been seldom used by the show's creators. Various episodes have set up the gag, sometimes presenting alternate explanations for Kenny's unacknowledged reappearances.
Still, the first, only, and last his voice was heard with his voice unmuffled speaking out loud (and not his thoughts inside his head like in "Turd Burglars") with his face completely unconcealed was in Bigger, Longer & Uncut.
Source : Wikipedia
