Greek alphabet glottal ("heth") was borrowed in two different functions by different dialects of Greek: as a letter for /h/ (Η, heta) by those dialects that had such a sound, and as an additional vowel letter for the long (Η, eta) by those dialects that lacked the consonant. Eventually, a seventh vowel letter for the long (Ω, omega) was introduced. Greek also introduced three new consonant letters for its aspirated plosive sounds and consonant clusters: Φ ("phi") for , Χ ("chi") for and Ψ ("psi") for . In western Greek variants, Χ was instead used for and Ψ for . The origin
Letter (alphabet) text than serif faces. Without serifs, an uppercase "I" () is indistinguishable from a lowercase "l" (). The average distribution of letters, or the relative frequency of each letter's occurrence in text in a given language, can be obtained by analyzing large amounts of representative text. This information can be useful in cryptography and for other purposes, such as song lyrics. Letter frequencies vary in different types of writing. Letter (alphabet) A letter is a grapheme (written character) in an alphabetic system of writing. It is a visual representation of the smallest unit of spoken sound. Letters broadly correspond to