I mean if the personal pronouns, copula, word order, core auxiliary and particle words, interrogatives and the like are the same between two languages separated

I mean if the personal pronouns, copula, word order, core auxiliary and particle words, interrogatives and the like are the same between two languages separated by time that's pretty good evidence that one is the ancestor of the other. More specifically to Chinese, if you read any comparative text on different Sinitic families, these word categories are the usual starting points of comparison between them and used to identify each. I haven't done the equivalent of examine 100 different word categories and only pick the 10 that prove my point. And every single Sinitic family other than Mandarin diverges from this list (as I explain in slightly more detail here: https://news.ycombinator.com/item?id=29533678 https://news.ycombinator.com/item?id=29533678).