Sha, alternatively transliteratedŠa (Ш ш; italics:Ш ш orШ ш; italics:Ш ш) is a letter of theGlagolitic andCyrillic scripts. It commonly represents thevoiceless postalveolar fricative/ʃ/, like the pronunciation of sh in "shoe". More precisely, the sound in Russian denoted by ш is often falsely transcribed as a palatoalveolar fricative, but is actually avoiceless retroflex fricative/ʂ/. It is used in every variation of the Cyrillic alphabet forSlavic and non-Slavic languages.[citation needed]
Sha has its earliest origins inPhoenicianShin and is possibly linked closely to Shin'sGreek equivalent:Sigma (Σ, σ, ς). (The similar form of the modernHebrewShin (ש), which is probably where the Cyrillic letter was actually derived from, derives from the sameProto-Canaanite source). Sha already possessed its current form inSaints Cyril and Methodius'sGlagolitic alphabet. Most Cyrillic letter-forms were derived from the Greek, but as there was no Greek sign for the Sha sound (modern Greek uses simply "Σ/σ/ς" to spell the sh-sound in foreign words and names), Glagolitic Sha (Ⱎ) was adopted unchanged. There is also a possibility that Sha was taken from theCoptic alphabet, which is the same as the Greek alphabet but with a few letters added at the end, including one called "shai" (Ϣϣ) which somewhat resembles both sha andshcha (Щ, щ) in appearance.
Sha is used in the alphabets of allSlavic languages using a Cyrillic alphabet, and of most non-Slavic languages which use a Cyrillic alphabet. The position in the alphabet and the sound represented by the letter vary from language to language.
In a different mathematical context, some authors allude to the shape of the letter Sha when they use the termShah function for what is otherwise called aDirac comb.
