My 20MO DD speaks in sentences (not just repeated words - if we are driving in the car and we stop, she will say 'mummy, the car has stopped' 'Where are we going mummy' 'no, I don't want to go to the swings, I want to feed quak quaks' 'please can we feed the quak quaks' - these are just examples today), counts (again, not just repeating numbers... I mean, she can count.. If you ask her 1+2, she will tell you 3. Today she counted the legs on a (picture) spider and said '6' (the correct answer).
She knows all of her letters (can sound them without prompting) and is excellent at drawing (she will draw a 'ceegle' (circle) or square or - actually anything you want!!... She (of her own accord) pointed out a walrus in her play animals today...
My DS (same age, they are twins) is nowhere near and I've been worried he's been behind (he sees speech therapist which is helping).. but my DD seems so... well.... advanced. And, I'm beginning to wonder whether I should be looking at ways to make sure she is fulfilled, as well as DS.