Chicago has a huge Mexican population, in the city of Elgin. It's so large that the Chicago Fire went after ex-America player Cuauhtemoc Blanco. I wouldn't fear the language at all. Once you put your child in a school with English only your child will be fine. Sure a little bit of a struggle, but people do it all the time. If it's a public school they will most likely have classes in English and Spanish. My younger brother teaches in the Public Schools and he's had a few classes when he was starting out that were only in Spanish. On a side note, as we are fans of Pumas UNAM, the kids called him Mr. Puma because he would wear his jersey.

Your best option would be to start with the public school system of the town you will be living in, if you know that. If you aren't sure where you'll be living, then your search will be tougher. But you can at least start here. A phone call can always save you a lot of time if you need an answer to a question not found through their webpage. Ask you company too be too, should be some people there with kids in the schools. Best wishes.

Chicago Public Schools