Life has been extremely busy that past few months - but the two kids are doing really well. Our second child isn't doing as well as our first child in terms of verbal development benchmarks (something like 100 to 120 words in English and maybe about the same in Chinese) but she seems to be doing well overall. For example, by 18 months our first child was singing full songs alone (Twinkle, Twinkle, etc.) but the second child can barely string two words together.
I think part of the issue with lesser level of advancement for the second child might be attributable to two things that the research has noted - first is that we had our second child 18 months after the first - and the research has indicated that for optimal health of the second (or later) child - you should have at least 27 months between babies births (it takes significant amount of time for the woman's body to recover, and the stored nutrition to return to a high level). Secondly - my wife got the flu at the end of the first trimester - and that is also associated with increased risk of mental and physical impact.
Interestingly, Physical development seems to be much better than the first child - but I suspect that part of that may be due to the fact that the second child can learn a great deal by following the first - and learning from the first child. But - while both children started walking at 9 months - only the second child was a great runner around the house by age 13 or 14 months. It took a number of additional months before the first child was running as strongly around the house.
Our first child is still doing well. She's 3 years old now, in her first year of preschool, and is the most socially advanced in her class (our teachers tell us) and also the most educationally advanced (counting, very fluent verbally in English and Chinese, etc.). So - things seem to be going well.
As always - feel free to email me questions.