I pick my child up from school and in the chaos of pickup hear so many different dialects. It seems that this (and other influences I'm sure) have created pockets and discourage engagement between parents. It's exclusive to everyone around.
Added to this the complexity of what it does for the kids, some I'm sure speak English fluently at home, others I'm sure another language. I'm in full support of multi lingual families - it just seems divisive and counter educational to speak a language other than that used in the course of the day/education on campus.
And I would support a similar approach to the Spanish immersion program.