Why is “colonel” pronounced “kurnel”?

Colonel is merely the English form of Italian colonello, .diminutive of colonna, “column,” and literally means “little column.” .At first the little column or company at the head of a regiment was .called eolonello, which in the’course of time was transferred to the leader or commander of the column or regiment. The term passed into French, English .and Spanish. In Spanish the form became coronel, and it was so spelled in English at first. It was pronounced Jcorr-6-nel. But the English gradually adopted the Italian spelling in abbreviated form, spelling it ^colonel and pronouncing it JcoII-o-nel. This pronunciation, for some reason, was later shortened to lurn-el, which became established about 1800. Some authorities suppose the r sound in colonel is merely a holdover from the days when the term was spelled and pronounced coronel. Since, however, the term was pronounced Jcolk>nel for two centuries, it seems more probable that the present pronunciation is owing to .a corruption in .speech rather than any influence of the .Spanish .spelling- The substitution of the r sound for the J sound is common in English as well as many other languages. In many parts of the United States colonel is colloquially pronounced Jcunn-el. Colonel is only one of the many cases in English where the pronunciation of a word has departed widely from ‘the spelling.