The excerpt quotes Dr Laura-Ann Petitto as saying that this indicates these areas of the brain control "fundamental features of language that can be expressed either through speech or signing."
It turns that Professor Petitto has a website. Here's her own synopsis of the matter,

Max, that is an important site to have pointed out. I printed off several of her articles and took home to read last night - I warmly commend them to everyone here, as I think her research is fundamental to understanding the relationship of our brain to language.
although, sadly, there are no mentions of baseball, recipes, jam, ink and all that other important stuff...