Latin script
Multigraphs

A digraph is a pair of letters used to write one sound or a combination of sounds that does not correspond to the written letters in sequence. Examples are ⟨ ch ⟩, ⟨ ng ⟩, ⟨ rh ⟩, ⟨ sh ⟩, ⟨ ph ⟩, ⟨ th ⟩ in English, and ⟨ ij ⟩, ⟨ ee ⟩, ⟨ ch ⟩ and ⟨ ei ⟩ in Dutch. In Dutch the ⟨ ij ⟩ is capitalized as ⟨ IJ ⟩ or the ligature ⟨ Ĳ ⟩, but never as ⟨ Ij ⟩, and it often takes the appearance of a ligature ⟨ ĳ ⟩ very similar to the letter ⟨ ÿ ⟩ in handwriting.

A trigraph is made up of three letters, like the German ⟨ sch ⟩, the Breton ⟨ c'h ⟩ or the Milanese ⟨ oeu ⟩. In the orthographies of some languages, digraphs and trigraphs are regarded as independent letters of the alphabet in their own right. The capitalization of digraphs and trigraphs is language-dependent, as only the first letter may be capitalized, or all component letters simultaneously (even for words written in title case, where letters after the digraph or trigraph are left in lowercase).
detectable_content:postscript, oulipo:avoid_letter[e]