Teletubbies are peak stopgap pedagogy. Lots of scientific backing.

Wait, hear me out. The whole show is set up so that you have repetitions of the same thing said at different levels of language acquisition so small kids can identify with whichever tubbie is at their level, look down a bit on the ones below that, and up to the ones above it (it goes all the way from pretty much baby speech to full adult). Thus their minds can climb the ladder.

Under normal circumstances that kind of setup is present in a child's environment -- differently-aged kids and adults, either in the family or neighbourhood, they get plenty of exposure. Now enter capitalism, alienation and atomisation and small kids get parked in front of the TV which might speak to them at a language level they aren't at, and can't react to them either, by translating their baby speech to more adult speech. Along come the Teletubbies, making sure that those kids at least have a resemblance of language skill once they reach school age.

And all that so the US can cut billionaire taxes to avoid paying for universal free daycare. Not that it should be taken off the air, also countries without that fucked of a situation air it because it doesn't hurt anyone and might help the occasional kid and the rest are merely entertained, but it's specifically the US combination of atrocious child rearing conditions (can't even play with other kids because you can't roam suburbia because that would get the parents arrested), combined with enough university resources to come up with the Teletubbies that, well, created the Teletubbies.