Romanization of Greek Greek numerals which employed the entire alphabet, including the nonstandard letters digamma, stigma, or sigma-tau (placed between epsilon and zeta), koppa (placed between pi and rho), and sampi (placed after omega). As revised in 2001, ELOT 743 provides for the uncommon characters to be given (in Greek) as $ for stigma, + for koppa, and / for sampi. These symbols are not given lower-case equivalents. When used as numbers, the letters are used in combination with the upper "keraia" numeral sign ⟨ʹ⟩ to denote numbers from 1 to 900 and in combination with the lower "keraia" ⟨͵⟩ to denote multiples
Archaic Greek alphabets , and was probably an intermediate sound during the phonetic change from the earlier plosive clusters towards the later sound, possibly an affricate similar to . In one attested document, the Arcadocypriot Greek of Mantineia used an innovative letter similar to И (), probably derived from a variant of san, to denote what was probably a -like sound in environments reflecting etymological Proto-Greek . In the highly-divergent Pamphylian Greek, the letter digamma () existed side by side with another distinctive form . It has been surmised that in this dialect the sound may have changed to labiodental in some environments.