EDIT Russian letter The 26th letter of the Russian alphabet is pronounced more or less like the English sh

Lower case letter corresponding to capital letter Ш (U+0428 CYRILLIC CAPITAL LETTER SHA)

Transliteration
international transliteration (ISO 9) - š (U+0161 LATIN SMALL LETTER S WITH CARON)
English transliteration (BSI, ALA) - sh

Origin
This letter originates from Cyrillitsa, which is one of the two systems the Russian alphabet is based on.

 fischer-hd