The common perception has been that children aren't exposed to enough data to arrive at their grammatical language skills, implying there's some proto language built in. Comparative analysis of languages has looked for what aspects are truly universal but there's actually not a lot of concrete true universals to ascribe to our genetic innate language.

But if it is genetic that doesn't really mean it's fundamentally different than ChatGPT, it just took a different and drastically longer training period and then transfer learning when children learn their mother tongue.