I don't know, but I know how to find out. If the kids on King of the Hill (sorry, I'm lousy with names) are played by actual kids then the characters will probably age. Otherwise the producers would have to continuously replace voice actors as the kids go through puberty. On the other hand, if the kids voices are played by adult women (as they are on The Simpsons) then the producers would have to replace the voice actors when the characters get to around age 13, so the characters would probably not age.
Really? I was told Pamela Segall played the voice of Bobby (just like most kids on the Simpsons are played by women).
I'm not sure who does Joseph's voice, although I wouldn't be surprised if it was also a woman. But, really, what other children do we have besides those two (Bobby and Joseph)? We have Kahn Jr., and we have that kid with the deep voice who sounds like Butthead (we don't know his name yet). There are also Randy and Garth from the Straight Arrow troop, but I have a feeling those two were just one-shot characters.
I've seen Luanne wear several different outfits -- case in point, her very short shorts in "Hank's Got the Willies" (4E05) or the outfit she wore to the square dance in "Luanne's Saga" (4E04). And the other characters seem to wear different clothes for different occasions -- Hank doesn't wear his normal blue jeans and white T-shirt on the golf course or at work.
Heh-heh... I remember at this time last year, someone over on alt.tv.simpsons kept asking why Ned Flanders kept wearing the same green sweater over and over again.
--Jason
"Luanne, would you _please_ not sit like that?!" --Hank Hill, "Hank's Got the Willies" (4E05)