ch

ch digraph used in Old French for the "tsh" sound. In some French dialects, including that of Paris, Latin ca- became French "tsha," whence the Old French spelling ch- for "tsh." This was introduced to English after the Norman Conquest, in words borrowed from Old French such as CHASTE (Cf. chaste), CHARITY (Cf. charity), CHIEF (Cf. chief). Under French influence, -ch- also was inserted into Anglo-Saxon words that had the same sound (e.g. BLEACH (Cf. bleach), CHEST (Cf. chest), CHURCH (Cf. church)) which in Old English had been written with a simple -c-, and into those that had formerly been spelled with a -c- and pronounced "k" such as CHIN (Cf. chin) and MUCH (Cf. much).

As French evolved, the "t" sound dropped out of it, so in later loan-words from France ch- has only the sound "sh-" (CHAUFFEUR (Cf. chauffeur), MACHINE (Cf. machine), CHIVALRY (Cf. chivalry), etc.).

It turns up as well in words from classical languages (CHAOS (Cf. chaos), ECHO (Cf. echo), etc.). Most uses of -ch- in Roman Latin were in words from Greek, which would be pronounced correctly as "k" + "h," as in blockhead, but most Romans would have said merely "k." Sometimes the -h- was written to keep the -c- hard before a front vowel, as still in modern Italian.

In some languages (Welsh, Spanish, Czech) ch- can be treated as a separate letter and words in it are alphabetized after -c- (or, in Czech and Slovak, after -h-). The sound also is heard in more distant languages (e.g. CHEETAH (Cf. cheetah), CHINTZ (Cf. chintz)), and the digraph also is used to represent the sound in Scottish LOCH (Cf. loch).