The Human Question

Scientists say that the speech areas (those that kick in when we are hearing or expressing) are larger in humans than in other primates.  Yes, but why?  I know it's supposed to be in our genes, but I can't help but wonder about how much of the larger size of these areas is a function of practices rather than DNA.  Consider the brain of a violinist: the area responsible for the control of his hand movement is larger than it is for non-violinists (who don't use hand skills with the same level of precision).  This largeness, however, is a function of practices.  It's large because he's a violinist rather than vice versa. Why can't the same be true for humans vis-a-vis non-humans?  In other words, it may be the case that humans have larger areas for communication than non-humans have for the same because humans are such intensive communicators.  Perhaps the average Joe is, in comparison to the bonono, a maestro at gesturing. I need to restudy about t...