http://news.discovery.com/human/bilingualism-language-brain-function.html
1. Speaking two or more languages appears to enhance executive function -- the ability to focus on the information needed to complete a task.
2. Bilinguals with Alzheimer's disease retained brain function longer than those who spoke only one language.
3. The "cost" of bilingualism is that bilinguals may have smaller vocabularies in each language.
