Why is there a need of language?
My God, it's obvious why we have language!
Try telling someone how to build a house with just yip, squeak, moo, bark, growl and grunt.
Also, I hear they have thousands of monkeys at typewriters, randomly banging away in the hopes that they write all the great classics. What purpose would they have then?
Also, what would talking parrots have to say?
I think you'll agree that these are all solid reasons to have language.
Seriously, mankind developed language thousands of years ago - how we still don't know. It must have help in our survival, because man has become the dominant species on the planet. Whether that is a good thing or not can always be argued.