Even if people around the 3-year old child talk to it 16 hours per day constantly at 150 words per minute, they'd just have around 1GB of text in its training data. And not good quality words even, a lot of it would be variations of mundane everyday chit chat and "whose a cute baby?! You're a cute baby!".

For comparison GPT has like 1TB of text, and they're hundreds of thousands of books, articles, wikipedia, and so on. So already 3 orders of magnitude more.

And of course the "16 hours x 150 words per minute x 3 years" is totally off by a few orders of magnitude itself.