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A digraph or digram (from the Greek: δίς dís "double" and γράφω gráphō "write") is a pair of characters used to write one phoneme (distinct sound) or a sequence of phonemes that does not correspond to the normal values of the two characters combined. The sound is often, but not necessarily, one which cannot be expressed using a single character in the orthography used by the language. Usually, the term "digraph" is reserved for graphemes whose pronunciation is always or nearly always the same.
When digraphs do not represent a distinct phoneme, they may be relics from an earlier period of the language when they did have a different pronunciation, or represent a distinction which is made only in certain dialects, like wh in English. They may also be used for purely etymological reasons, like rh in English.
In some language orthographies, like that of Croatian (lj, nj, dž), traditional Spanish (ch, ll) or Czech (ch), digraphs are considered individual letters, meaning that they have their own place in the alphabet, in the standard orthography, and cannot be separated into their constituent graphemes; e.g.: when sorting, abbreviating or hyphenating. In others, like English, this is not the case. In Dutch when the digraph 'ij' is capitalized, both letters are capitalized ('IJ').
Some schemes of Romanization make extensive use of digraphs (e.g. Cyrillic to Roman for English readers), while others rely solely on diacritics (e.g. Cyrillic to the modified Roman used for Turkish). To avoid ambiguity, transliteration based on diacritics is generally preferred in academic circles. Many languages, like Serbian (written in Cyrillic) and Turkish, have no digraphs, and so transliterations into these languages also cannot use digraphs.
Types of digraph 
Various patterns are discernible in the form of digraphs. In English, consonant digraphs tend largely to consist of some letter plus ⟨h⟩, or to be double letters. Doubling is a common digraph strategy in many orthographies.
Heterogeneous consonant digraphs in English include:
- ⟨ch⟩ usually corresponds to /tʃ/ (voiceless postalveolar affricate), to /k/ (voiceless velar plosive) when used as an etymological digraph in words of Greek origin, less commonly to /ʃ/ (voiceless postalveolar fricative) in words of French origin.
- ⟨ci⟩ usually appears as /ʃ/ before vowels.
- ⟨gh⟩ represents /ɡ/ (voiced velar plosive) at the beginning of words, represents /f/ (voiceless labiodental fricative) or is silent at the end of words.
- ⟨ng⟩ represents /ŋ/ (velar nasal).
- ⟨ph⟩ represents /f/ (voiceless labiodental fricative).
- ⟨qu⟩ usually represents /kw/; ⟨q⟩ is conventionally followed by u.
- ⟨rh⟩ represents English /r/ in words of Greek origin.
- ⟨sc⟩ normally represents /s/ (voiceless alveolar fricative) or /ʃ/ (voiceless postalveolar fricative) before ⟨e⟩ or ⟨i⟩.
- ⟨sh⟩ represents /ʃ/ (voiceless postalveolar fricative).
- ⟨th⟩ usually corresponds to /θ/ (voiceless interdental fricative) or /ð/ (voiced interdental fricative). See also Pronunciation of English ⟨th⟩.
- ⟨wh⟩ represents /hw/ in some conservative dialects; /w/ in other dialects; and /h/ in a few words where it is followed by ⟨o⟩, such as who and whole. See also Phonological history of ⟨wh⟩.
- ⟨wr⟩ represents /r/. Originally, it stood for a labialized sound, while ⟨r⟩ without ⟨w⟩ was non-labialized, but this distinction was lost in most dialects, the two sounds merging into a single alveolar approximant, allophonically labialized at the start of syllables, as in red [ɹʷɛd]. See also Rhotic consonant.
- ⟨zh⟩ represents /ʒ/ in words transliterated from Slavic languages, and in American dictionary pronunciation spelling.
Digraphs may also be composed of vowels. Common examples in English are:
- ⟨ai⟩ is usually pronounced /eɪ/.
- ⟨au⟩ is usually pronounced /ɔː/.
- ⟨aw⟩ is pronounced /ɔː/.
- ⟨ay⟩ is usually pronounced /eɪ/.
- ⟨ea⟩ is pronounced /iː/, /ɛ/, or more rarely /eɪ/.
- ⟨ee⟩ is pronounced /iː/
- ⟨ei⟩ is usually pronounced /aɪ/ or /eɪ/, or /iː/ after ⟨c⟩.
- ⟨eu⟩ is usually pronounced /juː/ or /uː/.
- ⟨ew⟩ is usually pronounced /juː/ or /uː/.
- ⟨ie⟩ is usually pronounced /iː/.
- ⟨oa⟩ is usually pronounced /oʊ/.
- ⟨oi⟩ is pronounced /ɔɪ/.
- ⟨oo⟩ is pronounced /uː/ or /ʊ/
- ⟨ou⟩ is usually pronounced /aʊ/, more rarely /uː/.
- ⟨ow⟩ is pronounced /aʊ/ or /oʊ/.
- ⟨oy⟩ is pronounced /ɔɪ/.
For further information on English, see English orthography.
There is also a split digraph, which has a consonant in between two vowels, e.g. ⟨asa⟩.
In some languages doubled letters indicate consonant length or vowel length, a stressed syllable or a specific sound, but in other cases they are just part of the spelling convention. ⟨Ll⟩ is the most common in English, though it does not represent a different sound from ⟨l⟩, being essentially an etymological digraph. In Welsh, however, ⟨ll⟩ stands for a voiceless lateral, and in Spanish and Catalan it stands for a palatal consonant. ⟨Ee⟩ and ⟨oo⟩ are vocalic examples from English.
In several languages of western Europe, including English, French and Catalan, ⟨ss⟩ is used between vowels for the voiceless sibilant /s/, since an ⟨s⟩ alone between vowels is normally voiced, /z/. In German, this digraph was fused into the ligature ß.
In Romance languages such as Spanish or Catalan, rr is used between vowels for the alveolar trill /r/, since an r alone between vowels represents an alveolar flap /ɾ/ (the two are different phonemes in these languages).
In Spanish the digraph nn, which used to indicate /ɲ/ (palatal nasal), was turned into the letter ñ, while ll indicates /ʎ/ (traditionally a palatal lateral approximant, though it has several dialectal variants in modern Spanish).
In Portuguese, the digraph nh indicates /ɲ/ (equivalent to Spanish ñ and to French and Italian gn), and lh indicates /ʎ/ (equivalent to Spanish ll).
In several Germanic languages, including English, CC (where C stands for a given consonant) corresponds to C and signifies that the preceding vowel is short.
Pan-dialectical digraphs 
Some languages have a unified orthography with digraphs that represent distinct pronunciations in different dialects (diaphonemes). For example, in Breton there is a digraph ⟨zh⟩ that is pronounced [z] in most dialects, but [h] in Vannetais. Similarly, the Saintongeais dialect of French has a digraph ⟨jh⟩ that is pronounced [h] in words that correspond to [ʒ] in standard French. Similarly, Catalan has a digraph ⟨ix⟩ that is pronounced [ʃ] in Eastern Catalan, but [jʃ] or [js] in Western Catalan–Valencian.
|Look up Category:English words with pseudo-digraphs in Wiktionary, the free dictionary.|
Some letter pairs should not be interpreted as digraphs, but appear due to compounding, like in hogshead and cooperate. This is often not marked in any way (it is an exception which must simply be memorized), but some authors indicate it either by breaking up the digraph with a hyphen, as in hogs-head, co-operate, or with a diaeresis mark, as in coöperate, though usage of a diaeresis has declined in English within the last century. This also occurs in names such as Clapham, Townshend, and Hartshorne, and is not marked here either.
In Romanization of Japanese, the constituent sounds (morae) are usually indicated by digraphs, but some are indicated by a single letter, and some with a trigraph. The case of ambiguity is the syllabic ん, which is written as n (or sometimes m), except before vowels or y where it is followed by an apostrophe as n'. For example, the given name じゅんいちろう is romanized as Jun'ichirō, so that it is parsed as /ju/n/i/chi/ro/u/, rather than as /ju/ni/chi/ro/u/.
In Czech also (and analogically in other Slavic languages), double letters may appear in compound words, but they are not considered digraphs. Examples: bezzubý (bez + zubý, toothless), cenný (cen + ný, valuable), černooký (černo + oký, black-eyed).
Discontinuous digraphs 
The pair of letters making up a phoneme are not always adjacent. This is the case with English silent e. For example, the sequence a…e has the sound /eɪ/ in English cake. This is the result of three historical sound changes: cake was originally /kakə/, the open syllable /ka/ came to be pronounced with a long vowel, and later the final schwa dropped off, leaving /kaːk/. Later still, the vowel /aː/ became /eɪ/.
However, alphabets may also be designed with discontinuous digraphs. In the Tatar Cyrillic alphabet, for example, the letter ю is used to write both /ju/ and /jy/. Usually the difference is evident from the rest of the word, but when it is not, the sequence ю...ь is used for /jy/, as in юнь /jyn/ 'cheap'.
The Indic alphabets are distinctive for their discontinuous vowels, such as Thai เ…อ /ɤː/ in เกอ /kɤː/. Technically, however, these are diacritics, not full letters; whether they are digraphs is thus a matter of definition.
Digraphs versus letters 
In some languages, digraphs and trigraphs are counted as distinct letters in themselves, and assigned to a specific place in the alphabet, separate from that of the sequence of characters which composes them, in orthography or collation. Other languages, such as English, make no such convention, and split digraphs into their constituent letters for collation purposes. A few language alphabets that include digraphs are:
- Bosnian, Croatian, Serbian. Note that in the Cyrillic orthography, these sounds are represented by single letters, rather than pairs of letters.
- Danish and Norwegian. Aa represented /ɔ/ until 1917 in Norway and 1948 in Denmark, but is today spelt å. The aa is still used in older names.
- cs represents /tʃ/ (voiceless postalveolar affricate)
- dz represents /dz/ (voiced postalveolar affricate)
- gy represents /ɟ/ (voiced palatal plosive)
- ly originally represented /ʎ/ (palatal lateral approximant), but in the modern language stands for /j/ (palatal approximant)
- ny represents /ɲ/ (palatal nasal)
- sz represents /s/ (voiceless alveolar fricative) (s is pronounced /ʃ/)
- ty represents /c/ (voiceless palatal plosive)
- zs represents /ʒ/ (voiced postalveolar fricative)
- The Hungarian alphabet additionally contains also a trigraph, dzs /dʒ/.
- ch corresponds to /x/ (voiceless velar fricative)
- cz corresponds to /tʂ/ (voiceless retroflex affricate)
- dz corresponds to /dz/ (voiced alveolar affricate)
- dź corresponds to /dʑ/ (voiced alveolo-palatal affricate)
- dż corresponds to /dʐ/ (voiced retroflex affricate)
- rz corresponds to /ʐ/ (voiced retroflex fricative)
- sz corresponds to /ʂ/ (voiceless retroflex fricative)
- Spanish. In addition to ll (see above), there is the digraph ch, which represents /tʃ/ (voiceless postalveolar affricate). Since 1994, neither are considered part of the alphabet. They used to be sorted as separate letters, but a reform in 1994 by the Spanish Royal Academy has allowed that they be split into their constituent letters for collation. The digraph rr, pronounced as a distinct alveolar trill, is considered to be a letter in the Spanish alphabet, however no words begin with rr, so it does not have a separate entry in Spanish dictionaries.
- Welsh. The digraphs listed below represent distinct phonemes. On the other hand, the digraphs mh, nh, and the trigraph ngh, which stand for voiceless consonants, but only occur at the beginning of words as a result of the nasal mutation, are not included in the alphabet.
- ch represents /x/ (voiceless velar fricative)
- dd represents /ð/ (voiced dental fricative), like the English th in then.
- ff represents /f/ (voiceless labiodental fricative), like English f, since Welsh f is pronounced like an English v.
- ll represents /ɬ/ (voiceless alveolar lateral fricative)
- ng represents /ŋ/ (velar nasal), the same sound as in English.
- ph represents /f/ (voiceless labiodental fricative)
- rh represents /r̥/ (voiceless alveolar trill), pronounced roughly like the combination hr.
- th represents /θ/ (voiceless interdental fricative)
In non-Latin alphabets 
Digraphs are found in alphabets other than the Latin alphabet.
Modern Greek has the following digraphs:
- αι (ai) represents /e̞/
- ει (ei) represents /i/
- οι (oi) represents /i/
- ου (oy) represents /u/
- υι (yi) represents /i/
These are called "diphthongs" in Greek; in classical times most of them did represent diphthongs, and the name has stuck.
- γγ (gg) represents /ŋɡ/ or /ɡ/
- τσ represents the affricate /ts/
- τζ represents the affricate /dz/
- Initial γκ (gk) represents /ɡ/
- Initial μπ (mp) represents /b/
- Initial ντ (nt) represents /d/
Ancient Greek also had the "diphthongs" listed above although their pronunciation in ancient times is disputed. In addition Ancient Greek also used the letter γ combined with a labial stop to produce the following digraphs:
- γγ (gg) represents /ŋɡ/
- γκ (gk) represents /ŋɡ/
- γχ (gkh) represents /ŋkʰ
Because vowels are not generally written, digraphs are rare in abjads like Arabic. For example, if sh were used for š, then the sequence sh could mean either ša or saha. However, digraphs are used for the aspirated and murmured consonants (those spelled with h-digraphs in Latin transcription) in languages of South Asia such as Urdu that are written in the Arabic script. This is accomplished with a special form of the letter h which is only used for aspiration digraphs, as seen with the following connecting (kh) and non-connecting (ḍh) consonants:
Urdu connecting non-connecting digraph: کھا /kʰɑː/ ڈھا /ɖʱɑː/ sequence: کﮩا /kəɦɑː/ ڈﮨا /ɖəɦɑː/
Modern Russian and other Slavic languages written in the Cyrillic alphabet makes little use of digraphs apart from ⟨дж⟩ for /dʐ/ (in loan words only in Russian, but used for native words in Bulgarian), ⟨дз⟩ for /dz/ (in loans), and ⟨жж⟩ for the uncommon Russian phoneme /ʑː/. Cyrillic only has large numbers of digraphs when used to write non-Slavic languages, especially Caucasian languages.
As was the case in Greek, Korean has vowels descended from diphthongs that are still written with two letters. These digraphs, ㅐ /ɛ/ and ㅔ /e/ (also ㅒ /jɛ/, ㅖ /je/), and in some dialects ㅚ /ø/ and ㅟ /y/, all end in historical ㅣ /i/.
Hangul was designed with a digraph series to represent the "muddy" consonants: ㅃ *[b̥], ㄸ *[d̥], ㅉ *[d̥z̥], ㄲ *[ɡ̊], ㅆ *[z̥], ㆅ *[ɣ̊]; also ᅇ, with an uncertain value. These values are now obsolete, but most of these doubled letters were resurrected in the 19th century to write consonants which had not existed when hangul was devised: ㅃ /p͈/, ㄸ /t͈/, ㅉ /t͈ɕ/, ㄲ /k͈/, ㅆ /s͈/.
Brahmi scripts 
Most Indic scripts have compound vowel diacritics that cannot be predicted from their individual elements. This can be illustrated with Thai, where the diacritic เ, on its own pronounced /eː/, modifies the pronunciation of other vowels:
single vowel sign: กา /kaː/, เก /keː/, กอ /kɔː/ vowel sign plus เ: เกา /kaw/, แก /kɛː/, เกอ /kɤː/
In addition, the combination รร is pronounced /a/ or /am/, there are some words where the combinations ทร and ศร stand for /s/ and the letter ห as prefix to a consonant changes its tonic class to high, modifying the tone of the syllable.
Hebrew and Yiddish 
In the Hebrew alphabet, תס and תש may sometimes be found for צ /ts/. Modern Hebrew also uses digraphs made with the ׳ symbol for non-native sounds: ג׳ /dʒ/, ז׳ /ʒ/, צ׳ /tʃ/; and other digraphs of letters when it is written without vowels: וו for a consonantal letter ו in the middle of a word, and יי for /aj/ or /aji/, etc., that is, a consonantal letter י in places where it might not have been expected. Yiddish has its own tradition of transcription, so uses different digraphs for some of the same sounds: דז /dz/, זש /ʒ/, טש /tʃ/, and דזש (literally dzš) for /dʒ/, וו /v/, also available as a single Unicode character װ, וי or as a single character in Unicode ױ /oj/, יי or ײ /ej/, and ײַ /aj/. The single-character digraphs are called "ligatures" in Unicode. י may also be used following a consonant to indicate palatalization in Slavic loanwords.
Japanese kana 
Two kana may be combined into a CV syllable by subscripting the second; this convention cancels the vowel of the first. This is commonly done for CyV syllables called yōon, as in ひょ hyo (⟨hiyo). These are not digraphs, as they retain the normal sequential reading of the two glyphs. However, some obsolete sequences no longer retain that reading, as in くゎ kwa, ぐゎ gwa, and むゎ mwa, now pronounced ka, ga, ma. In addition, non-sequenceable digraphs are used for foreign loans that do not follow normal Japanese assibilation patterns, such as ティ ti, トゥ tu, チェ tye / che, スェ swe, ウィ wi, ツォ tso, ズィ zi. (See Katakana and Transcription into Japanese for complete tables.)
Long vowels are written by adding the kana for that vowel, in effect doubling it. However, long ō may be written either oo or ou, as in とうきょう toukyou [toːkjoː] 'Tōkyō'. For dialects which do not distinguish ē and ei, the latter spelling is used for a long e, as in へいせい heisei [heːseː] 'Heisei'.
Okinawan kana 
There are several conventions of Okinawan kana which involve subscript digraphs or ligatures. For instance, in the University of the Ryukyus system, ウ is /ʔu/, ヲ is /o/, but ヲゥ is /u/.
Digraphs in Unicode 
Generally, a digraph is simply represented using two characters in Unicode. However, for various reasons, Unicode sometimes provides a separate code point for a digraph, encoded as a single character.
Latin alphabet 
Two Glyphs Digraph Unicode Code Point HTML DZ, Dz, dz Ǳ, ǲ, ǳ U+01F1 U+01F2 U+01F3 Ǳ ǲ ǳ DŽ, Dž, dž Ǆ, ǅ, ǆ U+01C4 U+01C5 U+01C6 Ǆ ǅ ǆ IJ, ij Ĳ, ĳ U+0132 U+0133 Ĳ ĳ LJ, Lj, lj Ǉ, ǈ, ǉ U+01C7 U+01C8 U+01C9 Ǉ ǈ ǉ NJ, Nj, nj Ǌ, ǋ, ǌ U+01CA U+01CB U+01CC Ǌ ǋ ǌ
See also Ligatures in Unicode.
Notes and references 
- !Claro Que Si! 3rd Edition 1996; Garner, Rusch, Dominguez; Houghton Mifflin Company; ISBN 0-395-74552-7; p.8
- "FAQ – Ligatures, Digraphs and Presentation Forms". The Unicode Consortium: Home Page. Unicode Inc. 1991–2009. Retrieved 2009-05-11.