Some of this is reviewed in the summary I sent out. There has been considerable research done on children, primarily in early French immersion programs, who are at risk for difficulty in school because of first language impairment due to cognitive difficulties, because they're from disadvantaged social class backgrounds. All of these factors usually are associated with students underachieving in school, in comparison with children who do not have these challenges. But when you look at the research results on these kinds of learners, you find that even children who have a language difficulty in their native language, or children who have below average intellectual ability, achieve just as well in immersion programs as similar students in a regular English program.
If you look at a child with language learning impairment in French immersion and compare them with a child with language learning impairment in an English only program, the immersion student does just as well in the first language and just as well in math and science as the student in the English program, and at the same time they are acquiring advanced competence in French.
There's not as much research on these children as we would like to see, and that's why I think we need more support to do that research. But so far, all of the research that has been done shows that children who have learning challenges in school are not more at risk for academic difficulty in an immersion program than in a monolingual English program.