#4: Double Letters

What is a digraph?  Well, there’s plenty of them in English and it’s where two ‘written letters’ represent one phonetic sound.  For example, in the word ‘phonetic’ the first two letters, <ph>, are actually only one phonetic sound – this sound can also be written more commonly as <f>, so, there’s not much need to explain what that sound means.  There are a wealth of reasons why certain writing systems may contain it, but for <ph>, the general rule of thumb is that these are morphemes (parts of words that have meaning) taken from the Greek lexicon and in Greek, the pronunciation of the /f/ sound is often softer in sounding because it is a slightly different sound to that that we have in English.

One interesting fact about the word ‘telephone’ is that the morphemes tele- and -phone, which mean distance and sound respectively, were stolen/borrowed/taken (whichever you prefer) from the Greek lexicon and put together to give a meaning resembling ‘sound from a distance’ – or something similar.  Once these morphemes were put together in English to make an English word, they entered our lexicons and were popular enough that Greek lexicons stole/borrowed/took back the word we made from their words and added it to their language in ‘telephono’.  I digress.


So, English, with its constantly odd spelling rules, has a lot of these double-letters, or digraphs, that are often put together to make one sound.  Some of these sounds, or phones – yes, from Greek – are glides between two vowel sounds that in our heads we see as one and these are known as diphthongs.  Romance languages don’t tend to have as many diphthongs as Germanic languages, and English has an unusual, great many vowels throughout its vast variety of dialects and accents.  Diphthongs are partly to blame for this and there at least eight distinct diphthongs in Standard RP English.

  • /eɪ/ as in the <ay> in ‘bay’ or the <a> in ‘bake’.
  • /aɪ/ as in the <uy> in ‘buy’ or the <i> in ‘bite’.
  • /ɔɪ/ as in the <oy> in ‘boy’ or the <oi> in ‘boil’.
  • /aʊ/ as in the <o> in ‘so’.
  • /əʊ/ as in the <ow> in ‘sow’.
  • /ɪə/ as in the <ea> in ‘ear’ or the <ee> in ‘steer’.
  • /eə/ as in the <ai> in ‘lair’ or the <a> in ‘stare’.
  • /ʊə/ as in the <u> in ‘pure’.

There are many more examples of this, and it is totally dependent upon your dialect as to how many of these you use.  If you are a speaker of Geordie dialects, you would tend to use a larger variety of diphthongs.  Due to English descending from the linguistic branch of the Germanic family, and its affinity for diphthongs, we also have triphthongs too.  Like diphthongs ‘gliding’ from one target vowel to another, triphthongs rather logically ‘glide’ exactly like a diphthong would and then to an additional target vowel afterwards giving three vowels in one sound.  In Cockney English they are particularly common, and here they are…

  • /aʊə/ as in the <ower> in ‘tower’.
  • /aɪə/ as in the <ire> in ‘tire’.
  • /ɔɪə/ as in the <oyer> in ‘toyer’.

Written strings of three letters would be consider trigraphs and some of these would include <our>, which also is a triphthong, <err>, <mmm>, <igh>.  Could there be any more vowels added on?  Could we, for instance, have a string of four letters representing one sound?  Or a glide of four target vowels that make one sound?

So words have subunits known as morphemes which have their own meaning, and these morphemes are made of syllables, just as words are.  Syllables themselves are made from an onset and a rhyme where the rhyme is made from a nucleus and a coda.  The coda is the final part of the syllable, whilst the onset is the first, and the nucleus is everything in between which primarily are vowels.  So in theory, there is nothing to say we cannot have four vowels within the nucleus of the syllable, it is just we don’t have any meaningful examples is any known living languages today (a string of vowels uttered when the speaker is thinking is the only example of a tetraphthong that I can think of).  Tetragraphs, however, do exist in English such as <ough> for words like ‘dough’ and ‘plough’ – and yes, you have had enough of ough – but they occur in other languages too like in French where <eaux> appears in ‘chateaux’ and ‘gateaux’ – though whilst it is a written tetragraph, it is phonetically a diphthong.

So, I hope I have not baffled you by strange combinations of written and spoken letters in digraphs and trigraphs, triphthongs and diphthongs, but I’m not quite done yet as I have only just talked about vowels – there’s some weird things that happen with ‘consonant’ digraphs that I’ll talk about next.

– DP, English Language and Linguistics student

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