Greek alphabet from which the later standard Greek alphabet emerged. Athens used a local form of the "light blue" alphabet type until the end of the fifth century BC, which lacked the letters Ξ and Ψ as well as the vowel symbols Η and Ω. In the Old Attic alphabet, stood for and for . was used for all three sounds (correspondinɡ to classical respectively), and was used for all of (corresponding to classical respectively). The letter (heta) was used for the consonant . Some variant local letter forms were also characteristic of Athenian writing, some of which were shared with the
Greek alphabet transcription systems, and to what degree they attempt either an exact letter-by-letter transliteration or rather a phonetically-based transcription. Standardized formal transcription systems have been defined by the International Organization for Standardization (as ISO 843), by the United Nations Group of Experts on Geographical Names, by the Library of Congress, and others. During the Mycenaean period, from around the sixteenth century to the twelfth century BC, Linear B was used to write the earliest attested form of the Greek language, known as Mycenaean Greek. This writing system, unrelated to the Greek alphabet, last appeared in the thirteenth century BC. In the