Digraph (orthography)

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For other uses, see Digraph.
In Welsh, the digraph Ll, ll fused for a time into a ligature.

A digraph or digram (from the Greek: δίς dís, "double" and γράφω gráphō, "to 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 Serbian Latin or Croatian (lj, nj, dž), traditional Spanish (ch, ll), Hungarian (cs, dz, dzs, gy, ly, ny, sz, ty, zs) 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. BGN/PCGN romanization of Russian), while others rely solely on diacritics (e.g. ISO 9 romanization of Russian). To avoid ambiguity, transliteration based on diacritics is generally preferred in academic circles. Orthographic transcription systems follow rules of their target language (i.e. the language of the readers for whom the systems are intended), so they cannot use digraphs if the target language has none.


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. Some scholars also describe a split digraph, which has a consonant in between two vowels.

Heterogeneous digraphs[edit]

Heterogeneous consonant digraphs in English include:

Digraphs may also be composed of vowels. Some letters a, e, o are preferred for the first position, others for the second i, u. The latter have allographs y, w in English orthography.

English vocalic digraphs
...e ...i ¦ ...y ...u ¦ ...w ...a ...o
o... oe¦œ > e – /i/ oi¦oy – /ɔɪ/ (SAE: /ɔːə/) ou¦ow – /aʊ¦aʊ̯¦uː (¦oʊ¦əʊ¦ɔʊ¦ʌ)/
(AUS: /æɔ¦æʊ/; CDN: /ʌʊ/; SSE: /ɘʉ/)
oa – /oʊ¦ɔː¦əʊ/ (US: /ɔʊ/) oo – /uː¦ʊ(¦u¦ʌ)/
e... ee – // ei¦ey – /aɪ¦eɪ¦(iː)/ eu¦ew – /juː¦uː/ ea – /iː¦ɛ¦(eɪ¦ɪə)/
a... ae¦æ > e – /i/ ai¦ay – /eɪ¦ɛ/ au¦aw – /ɔː/ (US: /ɑ¦ɑː¦ɔ/)
(in loanwords: // )
(in afro-American loanwords and proper nouns: aa – /ə¦ɔː¦ɔl/ ) (in loanwords from Chinese: ao – // )
u... ue – /uː¦u/ ui – /ɪ¦uː/ ua – /(ɒ¦ɑ)/
i... ie – /iː(¦aɪ)/

Homogeneous digraphs[edit]

In some languages doubled letters indicate consonant length (Italian) or vowel length (Finnish, Estonian), a stressed syllable or a specific sound, but in other cases they are just part of the spelling convention. The most common double letter in English is ll, 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. Vocalic examples from English are ee and oo .

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 letter 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.

In Basque, double letters mark palatalized versions as in dd, ll, tt. Note however that rr is a trill contrasting with the single-letter flap and that the palatal version of n is ñ.

In many European writing systems, including the English one, the doubling of the letter c or k is represented as the heterogeneous digraph ck instead of cc or kk respectively. In native German words, the doubling of z, which corresponds to /ts/, is replaced by the digraph tz.

Pan-dialectical digraphs[edit]

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 CatalanValencian.

Discontinuous digraphs[edit]

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.

Ambiguous letter sequences[edit]

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, so must be memorized as an exception. Some authors, however, indicate it either by breaking up the digraph with a hyphen, as in hogs-head, co-operate, or with a trema mark, as in coöperate, though usage of this diaeresis has declined in English within the last century. When it occurs in names such as Clapham, Townshend and Hartshorne, it is never marked in any way. Positional alternative glyphs may help to disambiguate in certain cases, e.g. when round s is used as a final variant of long ſ the English digraph resembling /ʃ/ would always be ſh.

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 , 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 /jun.i.chi.rou/, rather than as /ju.ni.chi.rou/.

In several Slavic languages, e.g. Czech, double letters may appear in compound words, but they are not considered digraphs. Examples: bezzubý ‘toothless’, cenný ‘valuable’, černooký ‘black-eyed’.

Digraphs versus letters[edit]

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:

Digraphs not considered letters[edit]

For English, see above.

French vocalic digraphs
...i ...u
a... ai – /ɛ¦e/ au – /o/
e... ei – /ɛ/ eu – /œ¦ø/
o... oi – /wa/ ou – /u(¦w)/
See also French phonology

In non-Latin alphabets[edit]

Digraphs are also found in alphabets that use scripts other than Latin.


In the Armenian language, the digraph ու corresponds to /u/, (close back rounded vowel).


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/

Tsakonian has a few additional digraphs: ρζ /ʒ/ (historically perhaps a fricative trill), κχ /kʰ/, τθ /tʰ/, πφ /pʰ/, σχ /ʃ/. In addition, palatal consonants are indicated with the vowel letter ι, but this is largely predictable. When /n/ and /l/ are not palatalized before ι, they are written νν and λλ.


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/


Main article: Cyrillic digraphs

Modern Russian and other Slavic languages written in the Cyrillic alphabet makes little use of digraphs apart from дж for /dʐ/, дз for /dz/ (in Ukrainian, Belarusian, and Bulgarian), and жж and зж for the uncommon Russian phoneme /ʑː/. In Russian, the sequences дж and дз do occur (mainly in loanwords), but are pronounced as combinations of an implosive (sometimes treated as an affricate) and a fricative; implosives are treated as allophones of the plosive /d̪/, so these sequences are not considered to be digraphs. Cyrillic only has large numbers of digraphs when used to write non-Slavic languages, especially Caucasian languages.


The Georgian alphabet uses a few diacritics when writing other languages. For example, in Svan, /ø/ is ჳე "we", and /y/ is ჳი "wi".


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/.


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.


Inuktitut syllabics adds two digraphs to Cree:

rk for q
qai, ᕿ qi, ᖁ qu, ᖃ qa, ᖅ q


ng for ŋ

The latter forms trigraphs and tetragraphs.


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׳ //, ז׳ /ʒ/, צ׳ //; 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 //, and דזש (literally dzš) for //, 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.


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'.


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/.

In Unicode[edit]

Generally, a digraph is simply represented using two characters in Unicode.[1] However, for various reasons, Unicode sometimes provides a separate code point for a digraph, encoded as a single character.

Latin alphabet[edit]

The DZ and IJ digraphs and the Serbian/Croatian digraphs DŽ, LJ, and NJ have separate code points in Unicode.

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 &#307
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.

See also[edit]

Notes and references[edit]

  1. ^ "FAQ – Ligatures, Digraphs and Presentation Forms". The Unicode Consortium: Home Page. Unicode Inc. 1991–2009. Retrieved 2009-05-11.