among the classical languages the Latin and the Greek languages play an utmost role in natural sciences, in medicine, history etc. It was only logical that those who discovered an element first or were involved in preparatory work to the built-up of the periodical system of elements made use of the classical languages to name the elements and used the two leading letters as an abbreviation for each of the chemical symbols, because the high-ranking English scientists then also availed themselves of these languages. Cobaltum (Co) is named after a little goblin (German: Kobold) which the ancient miners felt to have bewitched silver which they were primarily in search of. Iron originated from ferrum. Ir which you would like to use as symbol for iron is the symbol for iridium which derived from a Greek word to describe the outward appearrance "like a rainbow". Copper or cuprum may be traced back to the first mining operations on the Isle of Cyprus where they started mining it to produce bronzes (aes cyprium). There are good encyclopedias describing the "derivatio nominis".
Copper means Cuprum hence Cu for the abbreviation. Most elements are not English derived names as such the abbreviation originates from the native names.