The idea that housecats are baby-talking at humans when they meow is based on a misunderstanding.
Yes, it’s true that, amongst themselves, adult housecats generally only vocalise to communicate with kittens, but the particular set of vocalisations that adult cats use to communicate with humans is distinct from, and largely non-overlapping with, the set of vocalisations that they use to communicate with kittens.
Your average adult housecat has anywhere from twenty to fifty distinct vocalisations that are basically only used to communicate with humans.
Cats meowing at humans is less baby-talk and more your cat learning a whole second language.
Can confirm. Between themselves, cats usually use body language which is very subtle. Meowing is very unsubtle—- it’s obnoxious, in the cat world. It attracts far too much attention, which isn’t ideal for small predators.
but they know that we don’t get their body language, so they meow instead.
it’s more akin to cats learning a second language which is comprised of yelling.