I think it's one of those articles that gets upvoted because people like the topic. I'm getting old - what do. Same as random stuff regarding privacy, depression and google killing its projects.
So here we have generic discussion number #72, where we talk how neurogenesis stops at a certain age but not really and how stuff can improve your cognition but only if you're a mouse.
Also a good place to recommend The Brain That Changes Itself[1].
Nothing. Learning a new language at middle age is hard and demands a lot of effort.
Some languages are harder than others though. I leaned English in my twenties (20-25) it was easier than learning German (at 25+). Maybe that's because there is a lot of material in English compared to German (TV shows, Movies, Music).
I also tried Japanese, it's fairly easy to pick up daily phrases but reading/writing was almost impossible for me.