The 15th letter of the English alphabet is O. It is a vowel and is pronounced like the word "oh". The English alphabet consists of 26 letters, each having an uppercase and lowercase form. The alphabet originated around the 7th century to write Old English from Latin script, and since then, letters have been added or removed to give the current letters. The exact shape of printed letters varies depending on the typeface and font, and the standard printed form may differ significantly from the shape of handwritten letters, especially cursive.