Vilken jävla tur att jag både talar Engelska och Svenska flytande då !

-I guess I decreased that risk some then....  

Personally i think it would be more efficient to wait, and learn Chinese when were all prisoners of war!

I concur.  Most studies indicate that the most efficient time for humans to really learn a language is when they are very young.  Its sad that most school in the USA don't use multiple languages until Middle or High school.  For most of us, by then, the brain is already wired and the opportunity to learn language on deep level is diminished.  I'm a native English (well, "American") speaker, learned Spanish in High School.  I still do not follow Spanish conversation very well.  First generation immigrants often struggle with English.  Their children, however, often do very well.  New language as Alzheimer defense?  Gee, I forget if that's an issue for me.  

BTW, I read an article about 6 months ago about a new way to teach mandarin Chinese.  The idea, as i understood it, was to leanr the root images, and then learn how each add on changes, refines, the meaning of the image.  This is different from the more traditional rote memorization of 1000' so icons/pictographs.  Have you been exposed to this?  What do you think about it?

Yes I have Elana, I find it very helpful. I learned it in my 4th year of Uni Chinese after understanding the basics. You need to know the roots first which can take a while and then start piecing it together. Once you have learned enough words, you realize that every single word in Chinese is a combo of radicals and it becomes less intimidating. It is like boxing in a sense. You have jabs, straight punches, hooks and upper cuts. from those 5 different punches you can create combos to turn into an attack. But before combos are ever rehearsed you should first throw each punch well enough to progress. In English we may know how to pronounce a word that we don't know the definition of but in Chinese you will understand what the word means but may not know how to pronounce it.

I have never been good at memorizing Chinese words and writing them down. I am fortunate that I live in the computer age and can type Chinese which is much easier for me.

My grandmother who lived until 96 or therebouts was fluent in French and Italian. She had dementia not because of her language ability but because she never really had a community. 

Here is an article about languages and Alzheimer's  

http://news.nationalgeographic.com/news/2011/02/100218-bilingual-brains-alzheimers-dementia-science-aging/