diagraph
A digraph is a pair of letters that together represent a single sound in a language’s writing system. The term comes from the Greek dia- meaning “two” and graphe meaning “writing” or “letter.” Digraphs are a type of grapheme, the smallest unit of writing that maps to a phoneme, and they differ from monographs, which use a single letter for a sound, and from ligatures, which are typographic combinations that may or may not change pronunciation.
Digraphs function as a unit in the orthography of many languages, encoding sounds that cannot be represented
Common examples in English include ch, which represents /tʃ/ as in chair; sh, representing /ʃ/ as in
In linguistic analysis, digraphs are contrasted with other graphemic units such as trigraphs and multigraphs, and
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