"I letter" is the ninth letter of the English alphabet and is represented by the symbol "I." It is a vowel and can be pronounced as either a short "i" sound, as in "sit," or a long "i" sound, as in "time." In written form, it is often used to form words, such as "ice," "ink," or "idea." Additionally, "I" is also commonly used as a pronoun to refer to oneself.