Digraph (orthography)A digraph or digram (from the δίς , "double" and γράφω , "to write") is a pair of characters used in the orthography of a language to write either a single phoneme (distinct sound), or a sequence of phonemes that does not correspond to the normal values of the two characters combined. Some digraphs represent phonemes that cannot be represented with a single character in the writing system of a language, like the English sh in ship and fish. Other digraphs represent phonemes that can also be represented by single characters.