If you are serious about having your child develop a second language - consider school based programs within your own school district or state. I didn't even realized until I started searching that our district has its own dual immersion program for K-6th graders. The key to these programs is that you have to begin in kindergarten, children are not admitted at any other level unless they are transferring from another immersion program or can demonstrate proficieny in the secondary language. The Center for Applied Linguistics has a wealth of information from national immersion directories to trainings and research outcomes on dual immersion students. Check your local district or state for specific program info - some districts have programs that allow students to be immersed through the 12th grade!