Maybe their definition uses recent popularity or how many new projects are started with it. Under that definition, I think it's pretty safe to call it "dead".
Yes. "Dead" normally means "to be devoid of life," but it's often extended to metaphorically cover things like computer languages.
edit: for ancient Greek to become a dead language, will we be required to burn all of the books that were written in it, or can we just settle for not writing any new ones?
