David Robson of the BBC reports on the 2015 Polyglot Gathering in Berlin. The piece is interesting through out and makes the case that learning a new language is the best kind of brain training. It also includes lots of fascinating observations and advice:
“In the UK, Australia and US, it is easy to believe that we don’t need to make that effort. Indeed, before I met the hyperglots, I had wondered if their obsession merited the hard work; perhaps, I thought, it was just about bragging rights. Yet all of the hyperglots I meet are genuinely enthusiastic about the amazing benefits that can only be achieved by this full immersion in different languages – including the chance to make friends and connections, even across difficult cultural barriers.”
My current language interests are Japanese, Esperanto, and Sanskrit. However, because I am traveling to India next year, I will try to pick up some Hindi.
(Hat tip to Mind Hacks)
peakmemory 
Although I am sure there are many benefits of polyglottism, I think it isn’t very scientific to ask those people what the great benefits of being a polyglot is. Just knowing two of three languages has similar benefits like making friends across cultural barriers.
I would like to see more studies done about the benefits of these people. I know there are a few on bilingual or tri-lingual people, but not sure about people with 5+ languages.
Good point, there is research that suggests that being bilingual might improve cognition. Unfortunately, much of the research is correlational and, thus, we cannot infer causation.