The Dutch are amazing linguists! I'm always so impressed with Dutch travelers, they adjust so well to different languages and cultures. I have several Dutch friends here and they all speak at least 3 and some of them 5 languages. One of them is busy taking classes in Maya right now. We were in the market one day and she spoke Maya to one of the vendors, it knocked her socks off! She couldn't believe this blond was speaking to her in Maya. She told her she had a good accent and was very understandable.
I think that continuing to learn and be interested in new things does really keep your brain working better and keeps you feeling better too.