It's amazing how much more relaxed you become with your second birth. I would never have let the twins drink from big-boy cups at this age, let alone climb up the chair and sit without being buckled in.
I read an article the other day about how the second child recieves X fewer hours of quality time with Mom/Dad resulting in delayed book/letters/school type knowledge. Well, I beg to differ. I think the twin dynamic of a first birth severely alters common inferences. I have started introducing things to the toddler at a much younger age than I ever did with the twins: 1) because he seems interested; 2) because I talk a lot more this time around. I am in constant conversation with the twins and, thus, the toddler as well. I speak to them like they are people. The toddler may not sit still and look at the book when I read books, but he is in the room and absorbs it.
The toddler had his 18 month shots this morning and I had to fill out a development questionnaire. I like to be honest about these things, so for the question about whether he knows his body parts, I answered 'No.' Well the health nurse told my husband and I that we really needed to get started with that..... My husband quickly chimed in that he know lots of other words and those ones will come. As it so happens, I had just begun going over body parts with him in the last week.
I think back to the twins language development and remember how they barely said 'that' at 2 1/2 years old. The could understand each other perfectly, it was the rest of us who were behind in their language! Even today, the twins enunciation of words is way behind that of other children their own age, but those children didn't create their own language first and then start on another one - English.
Development - each to his/her own. I can't wait to see how the next one develops. I am sure it will be entirely different yet again.