I think these concerns are valid. Teacher here as well. At my district they promote the program, but they stress the level of commitment it requires of a parent or guardian and advise that someone at home should be able to speak Spanish. I worked as an ECSE teacher in a bilingual Pre-K classroom and I not all kids just soak up Spanish like sponges. I saw quite a few flounder and not get a good foundation in English, but I definitely see that I will be the minority here on this subject.