Ch is a digraph in the Latin script. It is treated as a letter of its own in Chamorro, Old Spanish, Czech, Slovak, Igbo, Uzbek, Quechua, Guarani, Welsh, Cornish, Breton, Ukrainian Łatynka and Belarusian Łacinka alphabets. Formerly ch was also considered a separate letter for collation purposes in Modern Spanish, Vietnamese, and sometimes in Polish; now the digraph ch in these languages continues to be used, but it is considered as a sequence of letters and sorted as such.
The digraph was first used in Latin since the 2nd century B.C. to transliterate the sound of the Greek letter chi in words borrowed from that language. In classical times, Greeks pronounced this as an aspirated voiceless velar plosive [kʰ]. In post-classical Greek (Koine and Modern) this sound developed into a fricative [x]. Since neither sound was found in native Latin words (with some exceptions like pulcher 'beautiful', where the original sound [k] was influenced by [l] or [r]), in Late Latin the pronunciation [k] occurred.
In Old French, a language that had no [kʰ] or [x] and represented [k] by c, k, or qu, ch began to be used to represent the voiceless palatal plosive [c], which came from [k] in some positions and later became [tʃ] and then [ʃ]. Now the digraph ch is used for all the aforementioned sounds, as shown below. The Old French usage of ch was also a model of several other digraphs for palatals or postalveolars: lh (digraph), nh (digraph), sh (digraph).
In Balto-Slavic languages that use the Latin alphabet instead of the Cyrillic alphabet, ch represents the voiceless velar fricative [x]. Ch is used in the Lithuanian language to represent the "soft h" /x/, in word choras [ˈxɔrɐs̪] "choir". This digraph is not considered a single letter in the Lithuanian alphabet. This digraph is used only in loanwords. "Ch" represents [kʰ] in Upper Sorbian.
In Czech, the letter ch is a digraph consisting of the sequence of Latin alphabet graphemes C and H, however it is a single phoneme (pronounced as a voiceless velar fricative [x]) and represents a single entity in Czech collation order, inserted between H and I. In capitalized form, Ch is used at the beginning of a sentence (Chechtal se. "He giggled."), while CH or Ch can be used for standalone letter in lists etc. and only fully capitalized CH is used when the letter is a part of an abbreviation (e.g. CHKO Beskydy) and in all-uppercase texts.
In the Czech alphabet, the digraph Ch is handled as a letter equal to other letters. In Czech dictionaries, indexes, and other alphabetical lists, it has its own section, following that of words (including names) beginning with H and preceding that of words that begin with I. Thus, the word chemie will not be found in the C section of a Czech dictionary, nor the name Chalupa in the C section of the phonebook. The alphabetical order h ch is observed also when the combination ch occurs in median or final position: Praha precedes Prachatice, hod precedes hoch.
Ch had been used in the Polish language to represent the "unvoiced h" /x/ as it is pronounced in the Polish word chlebpronunciation (help·info) "bread", and the h to represent "voiced h", /ɦ/ where it is distinct, as it is pronounced in the Polish word hakpronunciation (help·info) "hook". Between World War I and World War II, the Polish intelligentsia used to emphasize the "voiced h" to aid themselves in proper spelling. In most present-day Polish dialects, however, ch and h are uniformly merged as /x/.
In Slovak, ch represents /x/, and more specifically [ɣ] in voiced position. At the beginning of a sentence it is used in two different variants: CH or Ch. It can be followed by a consonant (chladný "cold"), a vowel (chémia "chemistry") or diphthong (chiazmus "chiasmus").
Only a few Slovak words treat CH as two separate letters, e.g., viachlasný (e.g. "multivocal" performance), from viac ("multi") and hlas ("voice").
In the Slovak alphabet, it comes between H and I.
In Goidelic languages, ch represents the voiceless velar fricative [x]. In Irish, ch stands for /x/ when broad and /ç/ (or /h/ between vowels) when slender. Examples: broad in chara /ˈxaɾˠə/ "friend" (lenited), loch /ɫ̪ɔx/ "lake, loch", boichte /bˠɔxtʲə/ "poorer"; slender in Chéadaoin /ˈçeːd̪ˠiːnʲ/ "Wednesday" (lenited), deich /dʲɛç/ "ten".
Breton has evolved a modified form of this digraph, c'h for representing [x], as opposed to ch, which stands for [ʃ]. In Welsh ch represents the voiceless uvular fricative [χ]. The digraph counts as a separate letter in the Welsh alphabet, positioned after c and before d; so, for example, chwilen 'beetle' comes after cymryd 'take' in Welsh dictionaries; similarly, Tachwedd 'November' comes after taclus 'tidy'.
Ch is the fifth letter of the Chamorro language and its sound is [ts]. The Chamorro Language has three different dialects - the Guamanian dialect, the Northern Mariana Islands dialect, and the Rotanese dialect. With the minor difference in dialect, the Guamanians have a different orthography from the other two dialects. In Guamanian orthography, both letters tend to get capitalized (e.g.: CHamoru). The Northern Mariana Islands' & Rotanese orthography enforces the standard capitalization rule (e.g.: Chamorro).
In several Germanic languages, including German and romanized Yiddish, ch represents the voiceless velar fricative [x]. In Rheinische Dokumenta, ch represents [x], as opposed to ch, which stands for [ç].
Dutch ch was originally voiceless, while g was voiced. In the northern Netherlands, both ch and g are voiceless, while in the southern Netherlands and Flanders the voiceless/voiced distinction is upheld. The voiceless fricative is pronounced [x] or [χ] in the north and [ç] in the south, while the voiced fricative is pronounced [ɣ] in the north (i.e. the northern parts of the area that still has this distinction) and [ʝ] in the south. This difference of pronunciation is called 'hard and soft g'.
In English, ch is most commonly pronounced as [tʃ], as in chalk, cheese, cherry, church, much, etc. When it represents [tʃ] word-medially or word-finally, it usually follows a consonant (belch, lunch, torch, etc.) or two vowels (beach, speech, touch, etc.). Elsewhere, this sound is usually spelled tch, with a few exceptions (attach, sandwich, lychee, etc.).
Ch can also be pronounced as [k], as in ache, choir, school and stomach. Most words with this pronunciation of ch find their origin in Greek words with the letter chi, like mechanics, chemistry and character. Others, like chiaroscuro, scherzo and zucchini, come from Italian.
In some English words of French origin, "ch" represents [ʃ], as in charade, machine, chivalry and nonchalant. Due to hypercorrection, this pronunciation also occurs in a few loanwords from other sources, like machete (from Spanish) and pistachio (from Italian).
In certain dialects of British English ch is often pronounced [dʒ] in two words: sandwich and spinach, and also in place names, such as Greenwich and Norwich.
In words of Scots origin it may be pronounced as [x] (or [k]), as in loch and clachan. In words of Hebrew or Yiddish origin it may be pronounced as [χ] (or [x]).
The digraph can also be silent, as in Crichton, currach, drachm, yacht and traditionally in schism.
In German, ch normally represents two allophones: the voiceless velar fricative [x] (or the voiceless uvular fricative [χ]) following a, o or u (called Ach-Laut), and the voiceless palatal fricative [ç] following any other vowel or a consonant (called Ich-Laut). A similar allophonic variation is thought to have existed in Old English.
The sequence "chs" is normally pronounced [ks], as in sechs (six) and Fuchs (fox).
An initial "ch" (which only appears in loaned and dialectical words) may be pronounced [k] (common in southern varieties), [ʃ] (common in western varieties) or [ç] (common in northern and western varieties). It is always pronounced [k] when followed by l or r, as in Chlor (chlorine) or Christus (Christ).
In Swedish, ch represents /ɧ/ and /ɕ/ in loanwords such as choklad and check. These sounds come from former [ʃ] and [tʃ], respectively. In the conjunction och (and), ch is pronounced [k] or silent.
The digraph ch is not considered part of the Hungarian alphabet, but it has historically been used for [tʃ], as in English and Spanish, and this use has been preserved in family names: Széchenyi, Madách. It is also retained in family names of German origin, where it is pronounced [h]: Aulich. The digraph is also used in some loan words, such as technika or jacht where it is pronounced [h].
In Interlingua, ch is pronounced /ʃ/ in words of French origin (e.g. 'chef' = /ʃef/ meaning "chief" or "chef"), /k/ in words of Greek and Italian origin (e.g. "choro" = /koro/ meaning "chorus"), and more rarely /t͡ʃ/ in words of English or Spanish origin (e.g. "cochi" /kot͡ʃi/ meaning "car" or "coach"). Ch may be pronounced either /t͡ʃ/ or /ʃ/ depending on the speaker in many cases (e.g. "chocolate" may be pronounced either /t͡ʃokolate/ or /ʃokolate/).
In Catalan ch represents final [k] sound. In the past it was widely used, but nowadays it is only present in some surnames (e.g. Domènech, Albiach). In medieval Catalan it was occasionally used to represent [tʃ] sound.
In native French words, ch represents [ʃ] as in chanson (song). In most words of Greek origin, it represents [k] as in archéologie, chœur, chirographier; but chimie, chirurgie, and chimère have [ʃ], as does anarchiste.
In Italian, ch represents the voiceless velar plosive [k] before -e and -i.
In Occitan, ch represents [tʃ], but in some dialects it is [ts].
In Portuguese, ch represents [ʃ], with some few speakers in northeastern mainland Portugal retaining the archaic [tʃ] (constrating with [ʃ] for x, homophonic elsewhere).
Ch is pronounced as a voiceless postalveolar affricate [tʃ] in both Castillian and American Spanish, or a voiceless postalveolar fricative [ʃ] in Andalusian.
Ch is traditionally considered a distinct letter of the Spanish alphabet, called che. In the 2010 Orthography of the Spanish Language, Ch is no longer considered a letter of its own but rather a digraph consisting of two letters.
Until 1994 ch was treated as a single letter in Spanish collation order, inserted between C and D; in this way, mancha was after manco and before manda. However, an April 1994 vote in the 10th Congress of the Association of Spanish Language Academies adopted the standard international collation rules, so ch is now considered a sequence of two distinct characters, and dictionaries now place words starting with ch- between those starting with ce- and ci-, as there are no words that start with cf- or cg- in Spanish. Similarly, mancha now precedes manco in alphabetical order.
Ch was used in the Massachusett orthography developed by John Eliot to represent a sound similar to /tʃ/ and in the modern orthography in use by some Wampanoag tribes for the same sound. In both systems, the digraph ch is considered a single letter.
In the Ossetic Latin alphabet, ch was used to write the sound [tsʰ].
In Palauan, ch represents a glottal stop [ʔ].
Ch represents [tʃ] in Uyghur Latin script.
Ch represents [tʃ] in the Uzbek alphabet. It is considered a separate letter, and is the 28th letter of the alphabet.
In Vietnamese, ch represents the voiceless palatal plosive [c] in the initial position. In the final position, the pronunciation is [jk̟̚].
In Xhosa and Zulu, ch represents the voiceless aspirated velar dental click [kǀʰ].
In Obolo, ch represents a [tʃ]. It is considered a single letter since 'c' and 'h' do not exist independently in the Obolo alphabet.
"Ch" is frequently used in transliterating into many European languages from Greek, Hebrew, Yiddish, and various others.
In Mandarin Chinese ch is used in Pinyin to represent an aspirated voiceless retroflex affricate /tʂʰ/.
In Japanese, ch is used in Hepburn to represent the chi sound (ち).
In many transliterations of Hebrew and Yiddish, the ch digraph is used to represent the voiceless uvular fricative /χ/, which is represented in Modern Hebrew by the letters ח and כ. Other transliterations systems will use the digraph kh to represent the same sound.
International Morse code provides a unitary code for Ch used in several non-English languages, namely — — — —.
In the Czech extension to Braille the letter Ch is represented as the dot pattern ⠻. English literary braille also has a single cell dedicated to ⟨ch⟩ (dots 1–6), which stands for "child" in isolation, but this is considered a single-cell contraction rather than a separate letter.
In English Braille, the "ch" digraph, when pronounced as [tʃ], is represented by a single cell:
In computing, Ch is represented as a sequence of C and H, not as a single character; only the historical KOI-8 ČS2 encoding contained Ch as a single character.