be in plain English

To be in clear, straightforward, and uncomplicated English. A: "Chronic atherosclerosis in the coronary arteries has stopped oxygen-rich blood from reaching the heart, leading to a myocardial infarction." B: "Doctor, come on, I need that to be in plain English." I wish these software agreements would be in plain English, rather than this legalese gobbledygook. None of these support sites are in plain English, and I can't understand all the technical jargon!