She is 2 now, but was the same as your DD at 1.
H can say full sentences, very clearly, and understands EVERYTHING we say.
We ask her to do 3 or 4 things, and she will say "all right", and toddle off and do them.

She is tall as well, so we get asked all the time if she 3 or 4.... .. umm, JUST turned 2!!!!

I cant list her words, she talks like her almost 5 yr old brother!

She really is remarkable, and I am very proud, and a little braggy too I guess.....

But out of 6 kids, I have had "early" kids, doing thinga a little earlier, but Harmony is the first to be actually so smart at only 2, so i dont think its all that common, but not uncommon, if that makes sense.
Your DD sounds like my DD1, very independant and ahead of herself.
DD1 is the same and i wonder if it's just DD2 being a parrot.