Because there's less cognitive overhead in learning 5 variations on one language to do 5 tasks than there is in learning 5 languages to do 5 tasks. You don't ha

Because there's less cognitive overhead in learning 5 variations on one language to do 5 tasks than there is in learning 5 languages to do 5 tasks. You don't have to relearn what semicolons, parentheses, braces, colons and so on mean. You just have to learn how inheritance works. Or the STL. Or whatever.