The Story of ch

The <ch> letter combination that Latin writers fashioned to represent the Greek letter (chi) in borrowed words, in Ancient Greek was a voiceless aspirated velar stop consonant [k^h], as in the English words keep or car, but by the time of Koine Greek, about two thousand years ago, it had changed its pronunciation to that of a voiceless velar fricative [x]. But more on that later. Among English words in which <ch> stands for [k] we find chasm, chromosome, chorus, chameleon, chamomile, chaos, character, characteristic,charisma, chasm, chemical, chemist, chemistry, chemotherapy, chimera, choir, chiropractor, chlorine, cholera, cholesterol, chord,choreograph, Christ, Christian, Christmas, Christopher, chronometer, chrysalis, and chrysanthemum.

Interestingly, the <ch> letter combination ended up being co-opted to represent a new sound that evolved in a language that evolved out of Latin in the old Roman province of Galia (pretty much equal to present-day France), namely French.  French is a Romance language, namely a language derived from the language of Rome, namely Latin. The new sound, which Latin did not have, was the sound that we now write with the digraph <ch>, as in cheap, which in the IPA is represented by the symbol [ʧ].  In Modern French <ch> represents a different sound, namely [ʃ], which is the sound typically written <sh> in English as in ship (but also differently in nation, ocean, machine, or mission). But in Medieval Norman French the digraph <ch> represented the sound it now typically has in English or Spanish.  When French speaking Normans invaded England in 1066 they brought such spelling practices with them. Until then English writers had used the letter <c> to represent two sounds: [k], as in cat, and also [ʧ], as in chat, what was from then on to be written with <ch>. So the spelling cin could represent either the word kin or the word chin.

It was to solve the ambiguity of the letter <c>, that English writers had started in the 9^th century already to sporadically use the letter <k>, which did not exist in the Latin alphabet and which was the Greek alphabet’s equivalent of Latin <c>, to represent the [k] sound in words like king and keen. This practice was fully established by the 13^th century. So now English has two major ways of representing the [k] sound, namely with the letter <c>, as in cat, and with the letter <k>, as in king. And <ch> came to be used to represent the sound [ʧ] in chin.

By the way, the English digraph <sh>, which represents the sound  [ʃ] in shop also stems from around this time. This was a new sound in English that developed out of the <sc> ([sk]) sound combination before certain vowels. Thus for a while <sc> spelled the sound [sk], as in skirt, but also the sound [ʃ], as in shirt. To distinguish between the two, English scribes started adding an <h> to the digraph to represent the latter sound. Thus a word like ship would be spelled schip (earlier it had been scip). This <sch> to represent the sound [ʃ] was later on simplified to <sh>. (In German this sound is still written <sch>.)

Going back to our original <ch> digraph, we can see now how it came to represent two sounds: [k] in words or Greek origin taken from written Latin, such as character, and [ʧ] in words taken from French words, such as cheap and champion.

As I was saying earlier, the Greek letter <Χ χ> (chi) which the Romans transliterated as <CH> and which was pronounced as aspirated [k^h] in classical Greek, changed its pronunciation in Medieval Greek. The sound of this letter (which looks a lot like the letter <x>) changed to the sound that in the International Phonetic Alphabet is represented, not coincidentally, with the symbol [x]. Modern English does not have this sound, but it exists in other European languages. This is the sound of <ch> in the German name Bach, or <ch> in Scottish Gaelic and Scottish English loch, meaning “lake”, as in Loch Ness.  It is also the sound of the letter <j> in many dialects of modern Spanish (e.g. José). (In some dialects of Spanish <j> represents the sound [h], which is the sound of the letter <h> in English hope, that is, when it is not silent, as in honor.)

It was because of the medieval sound of the Greek equivalent of Latin <CH> that some European languages, such as German,  used the <ch> digraph to represent this sound.  Spanish didn’t because the [x] sound is relatively recent in the history of the language and it grew out of other sounds which in some cases were written with the letter <j>, as jugar “to play” and some other cases with the letter <x>, as in xabon “soap”, now written jabón. The only common Spanish word with that sound that retained the <x> spelling is the word México, and then only in the Americas, not in Spain, where they write it Méjico.