You’re watching South Park, and Eric Cartman starts screaming at Kyle Broflovski. Then Randy Marsh walks in and says something incredibly stupid. It feels like a whole town of distinct people, but if you look at the credits, it’s basically just a few people in a room making funny noises. Honestly, it’s kind of wild that a show running since 1997 hasn't expanded its core cast to include dozens of A-list voice actors.
So, who does the voices on South Park? Most of the time, it's just Trey Parker and Matt Stone. They handle about 80% of the male characters. They don't just "do" the voices; they pitch their own vocals up or down using software to make an adult man sound like an eight-year-old with a bad attitude. If you've ever wondered why so many characters have that same nasal quality, well, now you know. It’s because they’re mostly coming out of Trey Parker’s throat.
The Two-Man Army: Trey and Matt’s Vocal Heavy Lifting
Trey Parker is the workhorse here. He voices the biggest chunk of the cast. We’re talking about Stan Marsh, Eric Cartman, Randy Marsh, and Mr. Garrison. Think about that for a second. The dynamic between Cartman and Stan—the two polar opposites of the show—is literally just one guy talking to himself.
He also does:
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- Mr. Mackey (M'kay?)
- Officer Barbrady
- Clyde Donovan
- Jimmy Valmer
- Stephen Stotch (Butters’ dad)
Then you’ve got Matt Stone. He handles the other half of the core four: Kyle Broflovski and Kenny McCormick. If you’ve ever wondered how Kenny’s muffled speech works, Matt literally just talks into his hand or the sleeve of his hoodie to get that "parka" sound. Beyond the kids, Matt voices Butters Stotch, which is arguably one of the most beloved voices in the series. He also does Gerald Broflovski, Jimbo Kern, and Craig Tucker.
The chemistry isn't just in the writing. It's in the fact that these two have been riffing off each other for nearly thirty years. When you see behind-the-scenes footage, they’re often in the booth together, trying to make each other crack up. That’s how you get those weird, improvised-feeling stutters or the specific way Randy Marsh says "Hey Sharon."
Who Handles the Women of South Park?
While Trey and Matt handle the guys, they generally stay away from the female roles—except for a few specific gags. Since 2004, the bulk of the female characters have been voiced by April Stewart and Mona Marshall.
April Stewart is a powerhouse. She voices Wendy Testaburger, Liane Cartman (Eric’s mom), Sharon Marsh, and Shelly Marsh. If a woman in South Park sounds authoritative or stressed out, it’s probably April. She’s mentioned in interviews that Principal Victoria was one of her toughest roles because of that specific Minnesotan accent.
Mona Marshall handles the other side of the fence. She is the voice of Sheila Broflovski (Kyle’s mom) and Linda Stotch. She’s been with the show since 1999, stepping in during a very difficult time for the production.
The Tragic History of the Female Cast
It’s important to talk about Mary Kay Bergman. In the first few seasons, she did almost every female voice on the show. She was a legendary voice actress who also worked for Disney and voiced Batgirl. Sadly, she passed away in 1999. After her death, the show cycled through a few actors, including Eliza Schneider, before settling on the current duo of April and Mona.
The Staffers Who Became Stars
South Park isn't exactly known for traditional casting calls. Often, if they need a new recurring character, they just look around the office.
Adrien Beard, who is actually a storyboard artist and producer on the show, voices Tolkien Black. He wasn’t a professional voice actor; they just needed someone to play the part, and he fit. The same goes for Jennifer Howell, a producer who voices Bebe Stevens.
Then there’s the case of Ike Broflovski. For years, Ike has been voiced by various children of the staff members. Currently, Trey Parker’s own daughter, Betty Boogie Parker, has provided the voice for Ike. It adds a level of authenticity to the "child" voices that you just can't get by having an adult mimic a toddler.
What About the Big Celebrities?
In the early days, South Park had a hilarious policy: if a big celebrity wanted to be on the show, they gave them the most insulting, minor role possible. George Clooney played Stan’s dog, Sparky. He literally just barked. Jay Leno voiced Cartman’s cat.
But as the show evolved, they started bringing in real guests for "actual" roles. Bill Hader is a huge one. He’s been a creative consultant and producer for years, and he pops up constantly as various background characters or specific parodies like Alec Baldwin.
And we can't forget Isaac Hayes. As Chef, he was the soul of the show for nearly a decade. His departure in 2006—due to the show’s parody of Scientology—was a massive turning point. Since then, the show hasn't really tried to replace that "soulful mentor" archetype. They just leaned harder into the chaos of the main cast.
How the Voices Actually Work: The "Pitching" Secret
If you heard Trey Parker record Stan Marsh in the studio, he would sound like a normal adult man. He doesn't do a "baby voice."
The South Park production team uses software (like Pro Tools or specialized plugins) to pitch the vocals up. They usually go up about three semitones. This keeps the performance's natural inflection and "acting" but makes it sound like it’s coming from a small child. It’s why the characters can sound genuinely angry or sad without it feeling like a caricature.
Matt Stone does the same thing for Kyle and Butters. If they didn't do this, the show would probably sound like a couple of guys in their 50s shouting in a basement—which, to be fair, is basically what it is, just with better tech.
Why This Matters for Fans
The reason South Park still feels like South Park after 26+ seasons is the consistency. Because Trey and Matt are the voices, the writers, and the directors, nothing gets lost in translation. There’s no "voice director" telling an actor how to say a line. The guy who wrote the joke is the guy screaming the joke into the microphone.
It’s a rare level of creative control that almost no other show in history has maintained for this long.
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Actionable Takeaways for Superfans
- Watch "Six Days to Air": If you want to see the actual recording process, this documentary is the gold standard. You can see Trey and Matt in the booth, and it’s surprisingly chaotic.
- Listen for the "Staff" Voices: Next time a minor character speaks, try to hear if it sounds like a professional actor or just a guy from the accounting department. It’s usually the latter.
- Check the Pitch: If you have audio editing software, try pitching a clip of Cartman down by 15-20%. You’ll hear Trey Parker’s normal speaking voice emerge like magic.
The "who" behind the voices isn't just a trivia fact; it's the reason the show works. It’s a small, tight-knit group of people who have turned a low-budget paper cutout show into a multi-billion dollar empire, all by refusing to hire a "proper" cast.