I'm a middle child of 3 and my little brother couldn't string a sentence together when he started reception, despite being NT.
My third child started walking at 10 months and is talking way sooner than my older two and I keep being told it's because he has older brothers (one is a teen and never here!).
Is it really because he's the third child? Or is it because every kid is different and he would always walk/talk at that particular age no matter at which point he was born?