My cousin does the "no baby talk" things and it has pretty good results. Their kids are sharp, but of course not in a Twittiot way. Just in a "get good grades and communicate coherently" way.

I baby talked my kids (now it’s Brain Rot). I also talk to them like an adult. I’ve always encouraged them to ask questions when they don’t understand something. My 9-year-old is not shy about stopping mid-conversation and asking what a word or phrase means.

I don't do baby talk because I just don't like it. Not to babies not to animals.

I do find baby talk irritating, but to each their own. As long as they don't say anything to me for no baby talking I won't say anything for those who baby talk.

But I will just say that I'm under the impression that baby talk is done more for the talker wanting to talk like that, rather that for the listener to have a easier understanding, as I was always understood the same without baby talking and just trying to use simpler words for smaller kids but without that cartoon voice.

I'm in Malaysia. Our politicians and a good segment of our adults encourage this kind of chat, esp during the lockdown, for fear of offending the spouse. They call it the 'doraemon voice' and it's as annoying as it sounds.