Substantive is also called line editing. 'They closely examine word choice, the impact of your writing and provide polish to make sure that your writing is clear and eloquent. Line editors will point out phrasing that sounds clichéd and suggest fixes for run-on sentences. They focus on clarity and will simplify your writing so that the meaning is clear and not overly convoluted.'
A native English reader can read this passage at about a pace of an estimated 1 to 5 pages an hour.