sound represented in O.E. by -sc- (e.g. fisc "fish"), which originally was pronounced "-sk-" but which by late O.E. had softened to "-sh-." Modern words with -sc- mostly are foreign (generally Scand.) imports. The "sh" sound did not exist in O.Fr., so Fr. scribes after the Norman conquest often represented it with -ssh- in medial and final positions, and sch- in initial positions. The spelling -sh- has been standard since Caxton, and probably is a worn-down form of M.E. -sch-. In some E. Anglian texts from 14c.-15c., x- is used (e.g. xal, xulde for shall, should), which would have given the language a very different look had it prevailed, but the London-based sh- ended up as the standard form.