I (eye), the ninth letter, is a vowel. Its original sound was.e in mete. The principal sounds are a long sound, as in pine, and a short one, as in pin. It also has the long and the short sound of e, as in machine and thirst. When it precedes another vowel, it is a consonantal y, as in Christian. The dot over I came in the 13th century. Originally I represented J too, J originating by lengthening I below the line. Until recently, even after J got into English dictionaries, words beginning with J were grouped with those beginning with I. The Romans used it as a numeral (1) as well as a letter.