The article linked below should be required reading. Especially for teachers, speech-language pathologists, and parents. (But really, everybody should know this.)
The article, “Recommending Monolingualism to Multilinguals – Why and Why Not” by Madalena Cruz-Ferreira, is featured on ASHA’s blog, and it explains the misconceptions people have about the effects of multilingualism on the brain in both disordered and normal speakers.
I cannot stress how important this information is. We currently have an educational system where even college professors** (some of whom teach language skills!) still believe these mythologies. It is incredibly important that this article is circulated widely. Please read it and pass the link along.
You can also check out her blog: Being Multilingual
**Please note that I highlight college professors here because they are supposed to be on the cutting edge of ongoing research so that they can best prepare a changing workforce–and train the incoming K-12 professionals. If we haven’t made progress with them, it’s no wonder so many others are confused.