I didnt notice that my 2 oldest girls may have been ahead till my son came along.
My girls now 5 and 4 both knew thier letters, shapes (more than circle, square, rectangle and triangle), and could count to 5 in english and spanish by 2 years old. They both were talking in complete sentences by 18 months and were understandable.
My son came along and didnt really talk till a week before his 2nd birthday. He said enough words but didnt put them together and refused to use them most of the time. The doctor told me he was normal. I asked what about my girls, they were average right? No but it was ok.
My son now can count to 10 only skipping the number 2, count backwards from 5. Still doesnt know his alphabet in english but can get to J in French, even though I say the English alphabet more often. He is able to name lots of stuff and speaks really well if not exceptionally for his age.
BUT I dont really care just waiting on an average kid, thats all I ever asked for but I think I am going to be stuck with 4 exceptional kids. My baby who is 18 months talks in complete sentences to me, not anyone else. She is understandable when she does decide to talk to someone else. She is interested in the potty and likes sitting on it. We will see what they all do.
All my kids have been shown shapes, colors and thier letters and numbers from birth, they are read to and talked to as though they will understand also from birth. But there is a wide difference in what they can do when.