<P> Celebrities who appear on the show are usually impersonated, though some celebrities lend their voice to their characters . Celebrities who have voiced themselves include Michael Buffer, Brent Musburger, Jay Leno, Robert Smith, and the bands Radiohead and Korn . Comedy team Cheech & Chong voiced characters representing their likenesses for the season four (2000) episode "Cherokee Hair Tampons", which was the duo's first collaborative effort in 20 years . Malcolm McDowell appears in live - action sequences as the narrator of the season four episode "Pip". </P> <P> Jennifer Aniston, Richard Belzer, Natasha Henstridge, Norman Lear, and Peter Serafinowicz have guest starred as other speaking characters . During South Park's earliest seasons, several high - profile celebrities inquired about guest - starring on the show . As a joke, Parker and Stone responded by offering low - profile, non-speaking roles, most of which were accepted; George Clooney provided the barks for Stan's dog Sparky in the season one (1997) episode "Big Gay Al's Big Gay Boat Ride", Leno provided the meows for Cartman's cat in the season one finale "Cartman's Mom Is a Dirty Slut", and Henry Winkler voiced the various growls and grunts of a kid - eating monster in the season two (1998) episode "City on the Edge of Forever". Jerry Seinfeld offered to lend his voice for the Thanksgiving episode "Starvin' Marvin", but declined to appear when he was only offered a role as "Turkey #2". </P> <P> Trey Parker voices four of the main characters: Stan Marsh, Eric Cartman, Randy Marsh and Mr. Garrison . He also provides the voices of several recurring characters, such as Clyde Donovan, Mr. Hankey, Mr. Mackey, Stephen Stotch, Jimmy Valmer, Timmy Burch, Tuong Lu Kim and Phillip . </P> <P> Matt Stone voices three of the main characters: Kyle Broflovski, Kenny McCormick and Butters Stotch . He also provides the voices of several recurring characters, such as Gerald Broflovski, Stuart McCormick, Craig Tucker, Jimbo Kern, Terrance, Saddam Hussein, Tweek Tweak, Mr. Adler and Jesus . </P>

Who does the voice of stan on south park