Digraph

A digraph or digram is a pair of characters (such as "sh") 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. 

Introduction and definition of digraph

A digraph is a single sound that is formed by joining together two alphabetical letters. Each letter wiithin an alphabet, represents its own sound; but the digraph is a new sound formed by the synthesis of the two letters. For example, the "s" in "silver" combined with a "h" sound in "hot" are different then when they are combined to form the "shh" sound in "shoe". 

Technically speaking, this new sound represented by the digraph would be a consonant or vowel all of its own. So, thanks to the digraph, virtually all languages have more consonants and/or vowels than they do actual letters in their alphabets. 

There are many forms of the digraph whose sounds can be predicted from the conjunction of letters involved. However, other forms of the digraph produce unique sounds that cannot be reduced to the individual letters. 

Digraph examples and rules

• The main rules for the formation of the digraph differ substantially across the various languages. In essence, the digraph always represents a sound that cannot be represented by a single letter of a given language. 
• A good example of the digraph within the English language is "sh", as described above. The way the tongue moves when pronouncing "sh" is different from the way it moves when pronouncing either of the component letters. The digraph is thus necessary in order to capture this unique consonant. Learn about consonants within the linguistics section.
• Some vowel sounds also require representation by a digraph. For example, there is the vowel sound "ae", which is drawn from Greek and often represented by the a and the e being combined into a single written character. This specific digraph may be hard to pronounce for many, due to the subtlety with which it is in fact neither of its component vowels. 

Additional information

One use of the digraph is to translate specific sounds from one language into the alphabet of another language. For example, the Russian language has a specific alphabetical letter that represents a sound that is not found within English. So, in English, that sound is normally rendered as the digraph zh. From reading this digraph, the English speaker can get a close-enough understanding of what is signified by the Russian single letter. 

The digraph thus fulfills an important function within the field of translation. This is also why foreign words and names may often contain letter combinations that are almost never found in English. 

Keep in mind that the digraph must always represent a single phoneme, or spoken sound. In this context, there are potentially several letter combinations that could not ordinarily become a digraph, due to the fact that the way the tongue moves when pronouncing the letters would not allow a single sound to emerge from their conjunction.  

However, an exception to this rule can be made when the digraph represents a totally new sound and is not reflective of the individual letters composing it. For example, hb could potentially be a digraph—but only under the assumption that this is a sound that has little to do with h by itself or b by itself. Again, this kind of strange conjunction in a digraph primarily emerges when translating foreign sounds into a native language.