I don't think you've met the assignment requirements. The rough draft will be a thematic outline. As such, it will describe, coherently and in detail, intended themes and sub-themes of the manuscript.
Language is nothing by itself.
I don't necessarily disagree with you. Nevertheless, I'd love to see your argument developed beyond the next sentence. Language as communication may offer many advantages. Other ways we communicate are with hand movements and expression, proximity to others, touching others, time, and our physical appearance. The best thing about language to me is the ability to describe events.