Even after 20 seasons, Trey Parker and Matt Stone still handle the vast majority of the voices on South Park. One exception to that, though, is Kyle Broflovski’s adopted Canadian brother, Ike, who, like all Canadians on the show, has a big, floppy two-part head, and, like all toddlers on the show, is voiced with incongruous realism by an actual toddler. Parker and Stone deliver their lines at a precise, staccato clip, making the juxtaposition with Ike’s realistic babble all the funnier.
This has been achieved consistently over two decades by cycling in different staff members’ kids to play him. Parker’s wife, Boogie, recently posted a video of her husband getting his 3-year-old daughter to deliver a couple typically profane lines.