"That answer is relatively boring, and is the same one as all evolutionary processes: it appeared randomly from mutation, and it provided benefit to those that had it."

Not just boring, but a totally banal and useless answer.

What kinds of mutations? In what sequence? How did it provide a survival benefit? What were the earlier forms of language like, and how did they become the languages spoken today?

Just saying "evolution did it" is about as informative as saying "God did it."