I remember reading that and thinking that it was really amazing how thinking about the two languages causes physical changes in the brain that not only delay dementia but cause better brain function in general. The article says that bi-lingual speaker's have been found to have a significant increase in in the brain's blood flow. It is just like developing a muscle in your body. I recently read Tony Buzan's book Mind Mapping and it shed some light on the truly amazing properties of the physical innerworkings of the brain. It makes you really realize just how much potential everyone has to do great things.