Hi all... I'm a teacher here in Santo Domingo and have worked here for the past 8 years at more than one school. I am a Canadian and currently work at one of the American accredited schools. I have read this thread several times and cannot stop myself from posting because I feel strongly that some of the information is not quite accurate.
First of all, many of the schools listed here as "bilingual" are not actually classified as bilingual, but rather as American schools. That being said, most schools are dual-language schools, meaning that most core subjects (language arts, social studies, math, science, etc.) are taught in English, but some subjects are taught in Spanish to fulfill the requirements of the Dominican Ministry of Education (like Spanish and sociales). Schools that fall in this category are St. Thomas, Dominico-Americano, St. Michael's, the American School, and many others. Students from these school graduate with both a US diploma and a Dominican diploma.
The only American school that doesn't require all of the Spanish classes is Carol Morgan, since it is the US Embassy school. Students there graduate with a US diploma, but not automatically with a Dominican diploma. They must elect to take the Spanish/Dominican stream if they want the Dominican diploma.
There are other schools that are truly classified as bilingual. In these schools, students take most classes in both languages. In other words, they take math in English and in Spanish, science in English and in Spanish, and so on. New Horizons is an example of a bilingual school.
I would also caution everyone strongly not to pay too much attention to the ratings of the Dominican government. I was working here when their survey of the schools took place. Much of the information they collected was not accurate and seemed to be politically motivated. For example, they said about the school where I work that our heads did not have any university degrees when, in fact, our heads each have at least one Master's degree each. They put other things in their report about our school such as that our receptionist had no desk, which was just laughable.
My overall advice is to do your own research and to do it in-depth. Go into the schools. Ask a lot of questions. The schools should be able to provide you with information about the teachers and their backgrounds (like where they are from and the degrees they have). I would recommend that you not be too swayed by outer appearances. As with everything here, some schools put a lot of stock into outer appearances and not much into real substance.
At the end of the day, I could give you my opinion about the schools, but it would be very biased and therefore ultimately not so useful. It really is best if people make up their minds for themselves. BTW, if you look in the yellow pages, you can find a pretty complete list of the English-language schools. Good luck to everyone searching!