The letter "U" is the 21st letter of the English alphabet. It is a vowel and has two sounds: the short sound /u/ and the long sound /ju:/ . The uppercase form of the letter "U" is "U," and the lowercase form is "u". The letter "U" is pronounced as "you" in English. In some words, such as "colour," "labour," and "valour," the letter "U" is used in British English, Canadian English, and other varieties of English, but in American English, it is not used, and these words are spelled as "color," "labor," and "valor".