Thank you for the lengthy response but I refuse to believe that lol. I’ve met so many Arabs who couldn’t pronounce a lot of the trickier letters even though they grew up with it. Immersing yourself in hours of study is enough to change it. When I studied Quran, it was maybe 20 hours a week for a couple of years.

Chinese is a different beast. But mastering a tricky language like Arabic will open up your ears to languages like Chinese. A big part is being able to “hear” the sounds properly so you know how to pronounce them.

Also, I’ve a friend who didn’t grow up with English and he got a perfect score on the verbal part for the Gre and is now going to Harvard law. If your grammar sucks, that’s on you, not because of some magical age barrier that prevents you from learning lol. Just because your professor said that, doesn’t make it right.