Jj is for Jottings 114.  Digraphs vs. Diphthongs.

Digraphs vs. diphthongs – what exactly are they and how do they differ?  They both begin with the same two letters, but then they diverge (get the pun?)

THE ROOTS OF DIGRAPHS AND DIPHTHONGS.

It is always helpful to understand the roots of words, because then we are able to transfer that learning to other situations.  It’s like teaching a man to fish rather than just giving him a fish.  (“Give a man a fish and you feed him for a day; teach a man to fish and you feed him for a lifetime.”  Maimonides.)  For a discussion of root words which underlie one of my pet peeves, see here.

Di.

In the case of digraphs and diphthongs, we have the common root “di”, which means “two”.  So both words involve two of something (as does “diverge”).

Phthong.

“Phthong” is a Greek root for human voice or animal cry, and by extension any sound.  There is another Greek root for sound: “phon”.  This refers to a sound or the human voice. Greeks also used it to mean ”vowel”.  Nobody seems sure why they used “phthong” instead of “phon” in “diphthong”, “monophthong” etc.  They certainly use “phon” a great deal: phonological, phonemic, phonics (see article) for starters.

Anyway, a diphthong refers to a sound that has two parts.  Click the link for a detailed explanation of diphthongs.

Graph.

“Graph” means “letter” or “writing”.  So a digraph is 2 letters that make one sound.

PUTTING IT ALL TOGETHER.

Using this knowledge, we can deduce that digraphs, trigraphs and quadgraphs relate to letters or the written representation of a sound.

Graphemes: The letter or groups of letters which represent one phoneme (sound). Grapheme is the umbrella term for graphs, digraphs, trigraphs and quadraphs.

Graph: 1 letter that makes one sound (e.g. l, m, s, t, e, a, etc.)

Digraphs:  2 letters that make one sound. These can be consonant digraphs (e.g. sh, ch, th, wh, ck) or vowel digraphs (ay, ai, ee, oi, etc.) .)  That is the story as it relates to teaching literacy. However, linguistically I would not include ch here, for reasons explained in this article.  Nor would I include ay, oe or ie, for reasons also outlined in the article about diphthongs.  However, for the purposes of literacy rather than linguistics, the digraph examples given above are fine.

Split digraphs: When a digraph is split by a consonant it becomes a split digraph. Some of you may know this as the ‘bossy-e’ or ‘magic-e’ rule.  The bossy ‘e’ rule is discussed in this article on short and long vowels.

Trigraphs: 3 letters that make one sound (e.g. ‘igh’ in high, ‘tch’ in witch).

As long as we remember that “graph” refers to the written form and “phon/phthong” refer to the spoken/sound form, we can often work out unfamiliar terms which use these roots.

DIGRAPHS VS. BLENDS.

First we had digraphs vs. diphthongs,now it’s digraphs vs. blends.  Aggressive little creatures, digraphs!

Digraphs are two letters that make one sound.  Blends, on the other hand, are two or more consonants that BLEND together but each sound can still be heard eg. st, pl.  Blends are also called consonant clusters, and there is a whole article devoted to them.

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