Shin (letter) languages, as follows: In the Arabic alphabet, ' is at the original (21st) position in Abjadi order. A letter variant ' takes the place of Samekh at 15th position. "" represents , and is the 13th letter of the modern alphabet order and is written thus: The Arabic letter "šīn" was an acronym for "something" ( "šayʾ(un)" ) meaning the unknown in algebraic equations. In the transcription into Spanish, the Greek letter "chi" (χ) was used which was later transcribed into Latin "x". According to some sources, this is the origin of "x" used for the unknown in the equations.
Latin alphabet alphabets may discard letters, like the Rotokas alphabet, or add new letters, like the Danish and Norwegian alphabets. Letter shapes have evolved over the centuries, including the development in Medieval Latin of lower-case, forms which did not exist in the Classical period alphabet. English is the only major modern European language requiring no diacritics for native words (although a diaeresis may be used in words such as "coöperation"). It is generally believed that the Romans adopted the Cumae alphabet, a variant of the Greek alphabet, in the 7th century BC from Cumae, a Greek colony in Southern Italy. (Gaius Julius