Immersion programs are great to learn another language. I don't think that a HG or even MG kid who is gifted in Math or Science would do any better in an immersion program than the average kid. Because giftedness is not uniform and studying Mandarin or Spanish or French for 50% of their time may or may not help the gifted child. OP, if you feel that languages are a strong point for your child, then this program will help. If not, I would not bother. In our case, my son does speak 3 languages, but his strength is in Math and English. He takes Spanish classes, but is not in an immersion program because I felt that it might be detrimental to his learning style.
My niece and nephew attended a French immersion private school until the 8th grade when they switched to an all english high school. They were grade skipped twice and have DYS level IQs and are very proficient in several fields (she in ballet and violin and he in tennis and debate). But, the transition to mainstream high school was hard for them because they learnt math and science in French. They had Ivy league ambitions and the potential to get there and now they are facing the reality of applying to a state university instead. Their family feels that the immersion program was a mistake for their kids who were interested in the STEM fields.
So, consider your child's strengths and weaknesses before you take the plunge.
