Multigraph (orthography)

A multigraph (or pleograph) is a sequence of letters that behaves as a unit and is not the sum of its parts, such as English $⟨ch⟩$ or French $⟨eau⟩$. The term is infrequently used, as the number of letters is usually specified:


 * Digraph (two letters, as English $⟨ch⟩$ or $⟨ea⟩$)
 * Trigraph (three letters, as French $⟨tch⟩$ or $⟨eau⟩$)
 * Tetragraph (four letters, as German $⟨tsch⟩$)
 * Pentagraph (five letters, as Avar $⟨чӀчӀв⟩$)
 * Hexagraph (six letters, as Irish $⟨oidhea⟩$)
 * Heptagraph (seven letters, as German $⟨schtsch⟩$)

Combinations longer than tetragraphs are unusual. The German pentagraph $⟨tzsch⟩$ has largely been replaced by $⟨tsch⟩$, remaining only in proper names such as $⟨Poenitzsch⟩$ or $⟨Fritzsche⟩$. Except for doubled trigraphs like German $⟨schsch⟩$, hexagraphs are found only in Irish vowels, where the outside letters indicate whether the neighboring consonant is "broad" or "slender". However, these sequences are not predictable. The hexagraph $⟨oidhea⟩$, for example, where the $⟨o⟩$ and $⟨a⟩$ mark the consonants as broad, represents the same sound (approximately the vowel in English write) as the trigraph $⟨adh⟩$, and with the same effect on neighboring consonants.

The seven-letter German sequence $⟨schtsch⟩$, used to transliterate Ukrainian $⟨щ⟩$, as in $⟨Borschtsch⟩$ for $⟨борщ⟩$ "borscht", is a sequence of a trigraph $⟨sch⟩$ and a tetragraph $⟨tsch⟩$ rather than a heptagraph. Likewise, the Juu languages have been claimed to have a heptagraph $⟨dts’kx’⟩$, but this is also a sequence, of $⟨dts’⟩$ and $⟨kx’⟩$.

Beyond the Latin alphabet, Morse code uses hexagraphs for several punctuation marks, and the dollar sign $⟨$⟩$ is a heptagraph, $⟨· · · — · · —⟩$. Longer sequences are considered ligatures, and are transcribed as such in the Latin alphabet.