For young children in early (K-5) foreign language immersion programs (e.g., Mandarin, Spanish, etc.), are these schools able to successfully work on general child development / social stuff in addition to the language stuff?

The short answer is yes. The longer answer is that it depends on the school, and that just as with non-immersion schools, there are some programs that put an emphasis on the development of the whole child, and there are others that focus on a narrower view of progress (e.g. teach to the test). One important thing to know about language immersion programs is that the kids don't learn the target language, but rather they learn IN the target language. What they learn, both academic curriculum and social development, depends entirely on what the teachers and staff focus on. The language acquisitions comes as a happy byproduct of spending the entire school day immersed in the target language. They don't have to "work harder" or compromise in other areas to learn the language, just as kids in an English program don't have to compensate for learning more English by being in History or Science or Math class in English. I am aware of at least two examples of schools who have been successful in combining Mandarin immersion with focus on the "whole child". The first is Presidio Knolls School (http://www.presidioknolls.org/), where I am a board member and parent. PKS is a Mandarin immersion preschool and elementary school with a Reggio Emilia inspired approach that very much focuses on the development of the whole child, including social and emotional development as well as intellectual development. The Ohlone Elementary (http://ohlone.pausd.org/) is a public Mandarin immersion elementary school in Palo Alto that also is very focused on the development of the whole child via the "Ohlone Way" which is more Montessori inspired but has similar ends in mind.

I teach French in a Foreign language program for children in the Washington DC area and through my own experience and what parents tell me I have noticed that some students really benefit from my classes on a developmental point of view. Because the communication happens in a language that the instructor and the child doesn't share entirely yet, the instructor uses all the possible ways to engage the student. As a result our classes are very creative and interactive. The children don't focus only on language but on all the other things linked to the language. We engage his/her curiosity, sense of humor, 5 senses, pleasure of moving and interacting abilities in general...